It is given that Indu and Jatin both scored 100% in exactly one section. We can say that Jatin scored 100% marks in DI. Therefore, Jatin's composite score = 2*20+16+14 = 70
It is given that Jatin’s composite score was 10 more than Indu’s. Therefore, we can say that Indu's composite score = 70 - 10 = 60.
Indu also scored 100% in exactly one section. 
Case 1: Indu scored 100% marks in DI.
If Indu scored 100% marks in DI, then Indu's score in GA = 60 - 2*20 - 8 = 12 which is less than 70% of maximum possible marks. Indu already has less than 70% in WE, therefore we Indu can't be recruited . Hence, we can reject this case. 
Consequently, we can say that Indu scored 100% marks in WE. Therefore, Indu's score in DI = $\dfrac{60-8-20}{2}$ = 16
It is also given that Danish, Harini, and Indu had scored the same marks the in GA. 

We are given that, among the four recruited, Geeta had the lowest composite score. 
Maximum composite score that Geeta can get = 2*14 + 6 + 20  = 54 {Assuming 100% marks in WE}. Since, Geeta was recruitedat a composite score of 54 or less we can say that Ester was definitely recruited. 
It is given that no two candidates had the same composite score. We can see that Chetna's composite score is 54. Hence, Geeta can't have a composite score of 54. Therefore, we can say that Geeta's composite score is 53 or less. 
We already know the four people(Jatin, Indu, Geeta, Ester) which were recruited. Hence, we cab say that Danish was rejected at a composite score of 51. Hence, we can say that Geeta's composite score in 52 or more. 
Consequently, we can say that Geeta's composite score if either 52 or 53. Therefore we can say that Geeta scored either 18 {52-(2*14+6)} or 19 {53-(2*14+6)} marks in WE. 

Ajay was the unique highest scorer in WE. 
Case 1: Geeta scored 19 marks in WE.
We can say that if Geeta scored 19 marks in WE, then Ajay scored 20 marks in DI. In that case Ajay's composite score = 2*8 + 20 + 16 = 52. Which is a possible case. 
Case 1: Geeta scored 18 marks in WE.
We can say that if Geeta scored 18 marks in WE, then Ajay can score either 19 or 20 marks in DI. 
If Ajay scored 20 marks in DI then in that case Ajay's composite score = 2*8 + 20 + 16 = 52 which will be same as Geeta's composite score. Hence, we can say that in this case Ajay can't score 20 marks.
If Ajay scored 19 marks in DI then in that case Ajay's composite score = 2*8 + 19 + 16 = 51 which will be same as Danish's composite score. Hence, we can say that in this case Ajay can't score 19 marks.
Therefore, we can say that case 2 is not possible at all.

Let us check all the statement one by one.
Option A: Bala scored same as Jatin in DI. We can say that Bala scored 20 marks in DI. In that Bala's composite score = 2*20 + 9 + 11 = 60 which is sam as Indu's composite score. Therefore, we can say that this is a false statement. Hence, option A is the correct answer. 

Let 'x' be the the number of Old visitors. Then, the number of middle-aged visitors = 2x.
Also, the number of Young visitors = 2*2x = 4x
$\Rightarrow$ x+2x+4x = 140
$\Rightarrow$ x = 20
It is given that total of 55 Economy tickets were sold out. 
It is given that Young visitors half the total number of Platinum tickets that were sold.
Let 'Y' be the number of Platinum tickets bought by the Young visitors. 
Then,the number of Platinum tickets sold = 2Y.
Consequently, we can say that the number of Gold tickets sold = 140 - 55 - 2Y = 85 - 2Y.

Let us assume that 'Z' is the number of Economy tickets bought by the Old visitors. It is given that the number of Gold tickets bought by Old visitors was equal to the number of Economy tickets bought by Old visitors.

It is given that the number of Old visitors buying Platinum tickets was equal to the number of Middle-aged visitors buying Platinum tickets.
20 - 2Z = (Y+2Z) - 20
Y + 4Z = 40
2Y + 8Z = 80
2Y = 80 - 8Z
We can see that Z can take only integer values. Therefore, we can say that the the total number of Platinum tickets sold will be a multiple of 8. Hence, option D is the correct answer.

Let 'x' be the the number of Old visitors. Then, the number of middle-aged visitors = 2x.
Also, the number of Young visitors = 2*2x = 4x
$\Rightarrow$ x+2x+4x = 140
$\Rightarrow$ x = 20
It is given that total of 55 Economy tickets were sold out. 
It is given that Young visitors half the total number of Platinum tickets that were sold.
Let 'Y' be the number of Platinum tickets bought by the Young visitors. 
Then,the number of Platinum tickets sold = 2Y.
Consequently, we can say that the number of Gold tickets sold = 140 - 55 - 2Y = 85 - 2Y.

Let us assume that 'Z' is the number of Economy tickets bought by the Old visitors. It is given that the number of Gold tickets bought by Old visitors was equal to the number of Economy tickets bought by Old visitors.

It is given that the number of Old visitors buying Platinum tickets was equal to the number of Middle-aged visitors buying Economy tickets.
20 - 2Z = 17 - Z
$\Rightarrow$ Z = 3
Therefore, we can say that the number of Old visitors buying Gold tickets = 3

Let 'x' be the the number of Old visitors. Then, the number of middle-aged visitors = 2x.
Also, the number of Young visitors = 2*2x = 4x
$\Rightarrow$ x+2x+4x = 140
$\Rightarrow$ x = 20
It is given that total of 55 Economy tickets were sold out. 
It is given that Young visitors half the total number of Platinum tickets that were sold.
Let 'Y' be the number of Platinum tickets bought by the Young visitors. 
Then,the number of Platinum tickets sold = 2Y.
Consequently, we can say that the number of Gold tickets sold = 140 - 55 - 2Y = 85 - 2Y.

Let us assume that 'Z' is the number of Economy tickets bought by the Old visitors. It is given that the number of Gold tickets bought by Old visitors was equal to the number of Economy tickets bought by Old visitors.

It is given that the number of Old visitors buying Gold tickets was strictly greater than the number of Young visitors buying Gold tickets.
Z > 42 - Y
$\Rightarrow$ Z + Y > 42 ... (1)
The number of Middle-aged visitors buying Gold tickets = 43 - (Y+Z)
Since (Y+Z) > 42, then We can say that (Y+Z)$_{min}$ = 43. 
Hence, the number of Middle-aged visitors buying Gold tickets = 43 - 43 = 0