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 calendar of the year 2060 can be used again in the year ? 
Options: a ) 2081 , b ) 2083 , c ) 2088 , d ) 1971 , e ) 1973
Example Output: c

Example Input: Problem: the profit earned by selling an article for rs . 753 is equal to the loss incurred when the same article is sold for rs . 455 . what should be the sale price for making 50 % profit ? 
Options: a ) 706 , b ) 786 , c ) 906 , d ) 896 , e ) 696
Example Output: c

Example Input: Problem: if it is assumed that 60 percent of those who receive a questionnaire by mail will respond and 300 responses are needed , what is the minimum number of questionnaires that should be mailed ? 
Options: a ) 400 , b ) 420 , c ) 480 , d ) 500 , e ) 600
Example Output:
d