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 length and breadth of a rectangle is increased by 10 % and 30 % respectively . what is the increase in the area ? 
Options: a ) 43.0 , b ) 44.0 , c ) 43.5 , d ) 45.0 , e ) 42.0

Ex Output:
a


Ex Input:
Problem: if the length of the sides of two cubes are in the ratio 4 : 1 , what is the ratio of their total surface area ? 
Options: ['a ) 4 : 1', 'b ) 6 : 1', 'c ) 8 : 1', 'd ) 16 : 1', 'e ) 64 : 1']

Ex Output:
d


Ex Input:
Problem: the slant height of a right circular cone is 10 m and its height is 8 m . find the area of its curved surface . 
Options: ['a ) 30 pi m ^ 2', 'b ) 40 pi m ^ 2', 'c ) 60 pi m ^ 2', 'd ) 80 pi m ^ 2', 'e ) 100 pi m ^ 2']

Ex Output:

c