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: if the diameter of circle r is 40 % of the diameter of circle s , the area of circle r is what percent of the area of circle s ? 
Options: a ) 16 % , b ) 18 % , c ) 20 % , d ) 22 % , e ) 24 %

Ex Output:
a


Ex Input:
Problem: if n is the smallest integer such that 144 times n is the square of an integer , what is the value of n ? 
Options: a ) 2 , b ) 3 , c ) 6 , d ) 12 , e ) 24

Ex Output:
a


Ex Input:
Problem: what is the radius of the incircle of the triangle whose sides measure 5 , 12 and 13 units ? 
Options: ['a ) 2 units', 'b ) 12 units', 'c ) 6.5 units', 'd ) 6 units', 'e ) 7.5 units']

Ex Output:

a