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: the annual interest rate earned by an investment increased by 11 percent from last year to this year . if the annual interest rate earned by the investment this year was 22 percent , what was the annual interest rate last year ? 
Options: a ) 17 % , b ) 19 % , c ) 18 % , d ) 20 % , e ) 22 %

Ex Output:
d


Ex Input:
Problem: if the simple interest on a certain amount in at 4 % rate 5 years amounted to rs . 2080 less than the principal . what was the principal ? 
Options: a ) 1500 , b ) 2600 , c ) 2507 , d ) 3200 , e ) 11500

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 $ 18.00 , how many discounted tickets did he buy ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 7

Ex Output:

c