In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: if each edge of cube increased by 30 % , the percentage increase in 
Options: a ) 69 , b ) 72 , c ) 64 , d ) 61 , e ) 75

Ex Output:
a


Ex Input:
Problem: 120 students represent x percent of the boys at a school . if the boys at the school make up 30 % of the total school population of x students , what is x ? 
Options: a ) 120 , b ) 150 , c ) 180 , d ) 200 , e ) 250

Ex Output:
d


Ex Input:
Problem: if the difference between compound interest ( interest compounded yearly ) and simple interest on a certain sum at the rate 20 % p . a . after 3 years is rs . 1280 then what is the principal ? 
Options: a ) 7900 , b ) 8,000 , c ) 10,000 , d ) 8,300 , e ) 9,300

Ex Output:

c