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'.

Example Input: Problem: the effective annual rate of interest corresponding to a nominal rate of 6 % per annum payable half - yearly is :
Options: a ) 6.09 % , b ) 6.08 % , c ) 6.1 % , d ) 6.07 % , e ) 6.05 %
Example Output: a

Example Input: Problem: ravi and kavi start a business by investing a ' 4000 and a ' 72000 , respectively . find the ratio of their profits at the end of year .
Options: a ) 2 : 28 , b ) 5 : 28 , c ) 7 : 18 , d ) 1 : 18 , e ) 3 : 18
Example Output: d

Example Input: Problem: a man took loan from a bank at the rate of 4 % p . a . s . i . after 10 years he had to pay rs . 2000 interest only for the period . the principal amount borrowed by him was ?
Options: a ) 5000 , b ) 4500 , c ) 3200 , d ) 6000 , e ) 1592
Example Output:
a