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 : 9 . find the ratio of their areas : 
Options: a ) 2 : 1 , b ) 4 : 7 , c ) 8 : 77 , d ) 4 : 81 , e ) none

Ex Output:
d


Ex Input:
Problem: a circular well with a diameter of 2 meters , is dug to a depth of 14 meters . what is the volume of the earth dug out . 
Options: ['a ) 40 m 3', 'b ) 42 m 3', 'c ) 44 m 3', 'd ) 46 m 3', 'e ) none of these']

Ex Output:
c


Ex Input:
Problem: the sum of a number and its square is 1406 . what is the number ? 
Options: ['a ) 1409', 'b ) 1402', 'c ) 1221', 'd ) 1406', 'e ) 8828']

Ex Output:

d