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: boys and girls in a class are writing letters . there are twice as many girls as boys in the class , and each girl writes 3 more letters than each boy . if boys write 24 of the 90 total letters written by the class , how many letters does each boy write ? 
Options: a ) 3 , b ) 4 , c ) 6 , d ) 8 , e ) 12

Ex Output:
d


Ex Input:
Problem: the population of a city increases by 7 % per year but due to migration it decrease by 1 % per years . what will be the percentage increase in population in 3 years ? 
Options: a ) 9 % , b ) 9.10 % , c ) 27 % , d ) 12 % , e ) none of these

Ex Output:
b


Ex Input:
Problem: what is 3 2 / 3 - 2 1 / 4 divided by 6 / 7 - 2 / 5 ? 
Options: a ) 17 / 36 , b ) 36 / 17 , c ) 17 / 64 , d ) 15 / 4 , e ) 14 / 4

Ex Output:

c