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: sam invested $ 1000 @ 20 % per annum for one year . if the interest is compounded half yearly , then the amount received by sam at the end of the year will be ?
Options: a ) $ 1542 , b ) $ 1145 , c ) $ 1210 , d ) $ 1642 , e ) $ 1020

Ex Output:
c

Ex Input:
Problem: what percent of 120 are 90 ?
Options: a ) 25 % , b ) 50 % , c ) 75 % , d ) 33 % , e ) 30 %

Ex Output:
c

Ex Input:
Problem: if tim had lunch at $ 50.50 and he gave 10 % tip , how much did he spend ?
Options: a ) $ 30.60 , b ) $ 60.60 , c ) $ 70.60 , d ) $ 55.55 , e ) $ 50.60

Ex Output:
d