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'.

Ex Input:
Problem: the average of 13 numbers is 60 . average of the first 7 of them is 57 and that of the last 7 is 61 . find the 8 th number ? 
Options: a ) 43 , b ) 30 , c ) 35 , d ) 45 , e ) 50

Ex Output:
a


Ex 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 %

Ex Output:
c


Ex Input:
Problem: if 100 < x < 199 and 20 < y < 100 , then the product xy can not be equal to : 
Options: a ) 1900 , b ) 19,303 , c ) 19 , 356.732 , d ) 19,502 , e ) 19,909

Ex Output:

a