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

Example Input: Problem: the radius of a cylinder is 2 r units and height is 3 r units . find the curved surface ? 
Options: a ) 18 π r 2 , b ) 12 π r 2 , c ) 3 π r 2 , d ) 6 π r 2 , e ) 9 π r 2
Example Output: b

Example Input: Problem: the radius of a sphere is increased by 10 % . the surface area increases by ? 
Options: ['a ) 21 %', 'b ) 31 %', 'c ) 41 %', 'd ) 51 %', 'e ) none of these']
Example Output: a

Example Input: Problem: in a company of 170 employees , 110 are females . a total of 80 employees have advanced degrees and the rest have a college degree only . if 25 employees are males with college degree only , how many employees are females with advanced degrees ? 
Options: a ) 40 , b ) 45 , c ) 50 , d ) 55 , e ) 60
Example Output:
b