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: how many internal diagonals does a hexagon ( 6 sided polygon ) have ? 
Options: a ) 5 , b ) 6 , c ) 8 , d ) 9 , e ) 10
Example Output: d

Example Input: Problem: the area of a rectangular plot is 18 times its breadth . if the difference between the length and the breadth is 10 metres , what is its breadth ? 
Options: a ) 10 metres , b ) 8 metres , c ) 7.5 metres , d ) data inadequate , e ) none of these
Example Output: b

Example Input: Problem: a circular garden is surrounded by a fence of negligible width along the boundary . if the length of the fence is 1 / 5 of th area of the garden . what is the radius of the circular garden ? 
Options: a ) 1 , b ) 2 , c ) 10 , d ) 8 , e ) 16
Example Output:
c