In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: a store reported total sales of $ 460 million for february of this year . if the total sales for the same month last year was $ 320 million , approximately what was the percent increase in sales ? 
Options: a ) 2 % , b ) 17 % , c ) 44 % , d ) 65 % , e ) 83 %
Example Output: c

Example Input: Problem: cost is expressed by the formula tb ^ 4 . if b is doubled , the new cost is what percent of the original cost ? 
Options: a ) 200 , b ) 600 , c ) 800 , d ) 1600 , e ) 50
Example Output: d

Example Input: Problem: if 2 x + y = 7 and x + 2 y = 5 , then 5 xy / 3 = ? 
Options: a ) a ) 5 , b ) b ) 2 , c ) c ) 17 / 5 , d ) d ) 18 / 5 , e ) e ) 4
Example Output:
a