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: a voltage will influence current only if the circuit is : 
Options: ['a ) 2', 'b ) 7', 'c ) 6', 'd ) 889', 'e ) 1']

Ex Output:
b


Ex Input:
Problem: the radius of a sphere is increased by 50 % . the increase in surface area of the sphere is : 
Options: a ) 168 , b ) 125 , c ) 186 , d ) 197 , e ) 191

Ex Output:
b


Ex Input:
Problem: what is the ratio between perimeters of two squares one having 8 times the diagonal then the other ? 
Options: a ) 3 : 6 , b ) 3 : 3 , c ) 3 : 8 , d ) 8 : 1 , e ) 3 : 2

Ex Output:

d