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: a survey was sent to 95 customers , 7 of whom responded . then the survey was redesigned and sent to another 63 customers , 9 of whom responded . by approximately what percent did the response rate increase from the original survey to the redesigned survey ? 
Options: a ) 2 % , b ) 5 % , c ) 7 % , d ) 28 % , e ) 63 %
Example Output: c

Example Input: Problem: the salary of a person was reduced by 10 % . by what percent should his reduced salary be raised so as to bring it at par with his original salary ? 
Options: a ) 10 % , b ) 11 1 / 9 % , c ) 13 2 / 7 % , d ) 15 3 / 11 % , e ) 12 1 / 3 %
Example Output: b

Example Input: Problem: walking 7 / 6 of his usual rate , a boy reaches his school 5 min early . find his usual time to reach the school ? 
Options: a ) 22 , b ) 28 , c ) 99 , d ) 35 , e ) 66
Example Output:
d