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 radius of a cylindrical vessel is 7 cm and height is 3 cm . find the whole surface of the cylinder ? 
Options: ['a ) 520 sq cm', 'b ) 840 sq cm', 'c ) 440 sq cm', 'd ) 120 sq cm', 'e ) 5 sq cm']

Ex Output:
c


Ex Input:
Problem: if the height of a cone is increased by 160 % then its volume is increased by ? 
Options: a ) 100 , b ) 777 , c ) 998 , d ) 729 , e ) 160

Ex Output:
e


Ex Input:
Problem: the height of two right circular cones are in the ratio 1 : 2 and their perimeters of their bases are in the ratio 3 : 4 , the ratio of their volume is ? 
Options: ['a ) 9 : 38', 'b ) 9 : 31', 'c ) 9 : 32', 'd ) 9 : 39', 'e ) 9 : 35']

Ex Output:

c