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: an escalator moves towards the top level at the rate of 7 ft . sec and its length is 180 feet . if a person walks on the moving escalator at the rate of 2 feet per second towards the top level , how much time does he take to cover the entire length .
Options: a ) 5 sec , b ) 25 sec , c ) 20 sec , d ) 15 sec , e ) 10 sec
Example Output: c

Example Input: Problem: if a lends rs . 3500 to b at 10 % per annum and b lends the same sum to c at 12 % per annum then the gain of b in a period of 3 years is ?
Options: a ) 200 , b ) 210 , c ) 220 , d ) 225 , e ) 230
Example Output: b

Example Input: Problem: in one alloy there is 12 % chromium while in another alloy it is 8 % . 15 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy . find the percentage of chromium in the new alloy .
Options: a ) 8.8 % , b ) 9 % , c ) 9.2 % , d ) 8.6 % , e ) 8.4 %
Example Output:
c