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: how long will a boy take to run round a square field of side 50 meters , if he runs at the rate of 10 km / hr ? 
Options: a ) 52 sec , b ) 45 sec , c ) 72 sec , d ) 25 sec , e ) 39 sec
Example Output: c

Example Input: Problem: the cost price of a radio is rs . 1500 and it was sold for rs . 1110 , find the loss % ? 
Options: a ) 18 , b ) 16 , c ) 26 , d ) 17 , e ) 11
Example Output: c

Example Input: Problem: at what rate percent on simple interest will rs . 415 amount to rs . 514 in 4 years ? 
Options: a ) 4.58 % , b ) 5.96 % , c ) 6.52 % , d ) 4.98 % , e ) none of these
Example Output:
b