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: how many liters of a 40 % iodine solution need to be mixed with 35 liters of a 20 % iodine solution to create a 32 % iodine solution ? 
Options: a ) 35 , b ) 49 , c ) 100 , d ) 102 , e ) 140

Ex Output:
d


Ex 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

Ex Output:
e


Ex Input:
Problem: simple interest on a certain sum of money for 2 years at 12 % per annum is half the compound interest on rs . 6000 for 2 years at 15 % per annum . the sum placed on simple interest is 
Options: a ) rs . 6000 , b ) rs . 7935 , c ) rs . 8265.63 , d ) rs . 3967.5 , e ) none

Ex Output:

c