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: at an election 2 candidates are participated and a candidate got 20 % of votes and defeated by 500 . and 10 votes are invalid . find the total polled votes ? 
Options: a ) 843 , b ) 1023 , c ) 965 , d ) 413 , e ) 1245
Example Output: a

Example Input: Problem: what percent of 120 are 90 ? 
Options: a ) 25 % , b ) 50 % , c ) 75 % , d ) 33 % , e ) 30 %
Example Output: c

Example Input: Problem: a man gains 20 % by selling an article for a certain price . if he sells it at double the price , the percentage of profit will be . 
Options: a ) 130 % , b ) 140 % , c ) 150 % , d ) 160 % , e ) 170 %
Example Output:
b