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 statue is being carved by a sculptor . the original piece of marble weighed 250 kg . in the first week 30 per cent is cut away . in the second week 20 per cent of the remainder is cut away . in the third week the statue is completed when 25 percent of the remainder is cut away . what is the weight of the final statue ? 
Options: a ) 105 kg , b ) 145 kg , c ) 165 kg , d ) 115 kg , e ) 100 kg
Example Output: a

Example Input: Problem: if it is assumed that 60 percent of those who receive a questionnaire by mail will respond and 900 responses are needed , what is the minimum number of questionnaires that should be mailed ? 
Options: a ) 1300 , b ) 1350 , c ) 1400 , d ) 1450 , e ) 1500
Example Output: e

Example Input: Problem: what will be the compound interest on a sum of rs . 25,000 after 3 years at the rate of 12 p . c . p . a . ? 
Options: a ) rs . 9000.30 , b ) rs . 9720 , c ) rs . 10123.20 , d ) rs . 10483.20 , e ) none of these
Example Output:
c