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: what is the rate percent when the simple interest on rs . 4000 amount to rs . 320 in 2 years ? 
Options: a ) 4 % , b ) 4.1 % , c ) 4.2 % , d ) 4.3 % , e ) 4.5 %

Ex Output:
a


Ex Input:
Problem: 30 is what percent of 100 ? 
Options: a ) 35 % , b ) 30 % , c ) 45 % , d ) 50 % , e ) 55 %

Ex Output:
b


Ex Input:
Problem: martin bought 10 concert tickets , some at the full price of $ 2.00 per ticket , and some at a discounted price of $ 1.60 per ticket . if he spent a total of $ 17.60 , how many discounted tickets did he buy ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 7

Ex Output:

d