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 the base of cone is 3 cm and height is 4 cm . find the volume of the cone ?
Options: ['a ) 12', 'b ) 75', 'c ) 97', 'd ) 15', 'e ) 91']
Example Output: a

Example Input: Problem: rectangle a has sides a and b , and rectangle b has sides c and d . if a / c = b / d = 4 / 5 , what is the ratio of rectangle a ' s area to rectangle b ' s area ?
Options: a ) 5 / 4 , b ) 25 / 16 , c ) 4 / 5 , d ) 16 / 25 , e ) 16 / 5
Example Output: d

Example Input: Problem: the difference of the areas of two squares drawn on two line segments of different lengths is 32 sq . cm . find the length of the greater line segment if one is longer than the other by 2 cm .
Options: a ) 6 cm , b ) 7 cm , c ) 9 cm , d ) 11 cm , e ) none
Example Output:
c