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: if the cost price of 55 articles is equal to the selling price of 50 articles , then what is the percent profit ? 
Options: a ) 5 % , b ) 10 % , c ) 15 % , d ) 20 % , e ) 25 %

Ex Output:
b


Ex Input:
Problem: a trader bought a car at 20 % discount on its original price . he sold it at a 55 % increase on the price he bought it . what percent of profit did he make on the original price ? 
Options: a ) 17 % , b ) 24 % , c ) 12 % , d ) 82 % , e ) 16 %

Ex Output:
b


Ex Input:
Problem: each month a retailer sells 100 identical items . on each item he makes a profit of $ 30 that constitutes 16 % of the item ' s price to the retailer . if the retailer contemplates giving a 5 % discount on the items he sells , what is the least number of items he will have to sell each month to justify the policy of the discount ? 
Options: a ) 157 , b ) 213 , c ) 221 , d ) 223 , e ) 226

Ex Output:

a