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

Ex Input:
Problem: the ratio of radius of a circle and the side of a square is 2 : 3 . find the ratio of their areas : 
Options: a ) 2 : 1 , b ) 4 : 9 , c ) 8 : 77 , d ) 4 : 121 , e ) none

Ex Output:
b


Ex Input:
Problem: the number 155 can be written as the sum of the squares of 3 different positive integers . what is the sum of these 3 integers ? 
Options: a ) 17 , b ) 16 , c ) 15 , d ) 14 , e ) 21

Ex Output:
e


Ex Input:
Problem: how many internal diagonals does a heptagon ( seven sided polygon ) have ? 
Options: a ) 7 , b ) 9 , c ) 14 , d ) 20 , e ) 35

Ex Output:

c