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 bases of a hemisphere and a cone are equal . if their heights are also equal then ratio between their curved surface area is — 
Options: ['a ) 1 : √ 2', 'b ) √ 2 ∶ 1', 'c ) 1 : 2', 'd ) 2 : 1', 'e ) none of these']
Example Output: b

Example Input: Problem: the area of the house of a hall is 20 m 2 that of a longer wall 10 m 2 and of the shorter wall 8 m 2 , find the edge of the new cube ? 
Options: ['a ) 45 m 3', 'b ) 40 m 3', 'c ) 60 m 3', 'd ) 600 m 3', 'e ) 300 m 3']
Example Output: b

Example Input: Problem: a rectangular block 6 cm by 12 cm by 15 cm is cut into an exact number of equal cubes . find the least possible number of cubes ? 
Options: a ) 20 , b ) 25 , c ) 40 , d ) 50 , e ) 35
Example Output:
c