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: 90 students represent x percent of the boys at jones elementary school . if the boys at jones elementary make up 40 % of the total school population of x students , what is x ? 
Options: a ) 125 , b ) 150 , c ) 225 , d ) 250 , e ) 500
Example Output: b

Example Input: Problem: sarah operated her lemonade stand monday through friday over a two week period and made a total profit of 350 dollars . on hot days she sold cups of lemonade for a price that was 25 percent higher than the regular days . each cup she sold had a total cost of 75 cents and sarah did not incur any other costs . if every day she sold exactly 32 cups and 4 of the days were hot , then what was the price of 1 cup on a hot day ? 
Options: a ) $ 1.50 , b ) $ 1.88 , c ) $ 2.09 , d ) $ 2.50 , e ) $ 3.25
Example Output: c

Example Input: Problem: a reduction of 25 % in the price of oil enables a house wife to obtain 5 kgs more for rs . 500 , what is the reduced price for kg ? 
Options: a ) 25 , b ) 60 , c ) 70 , d ) 80 , e ) 20
Example Output:
a