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: 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


Ex Input:
Problem: a circular well with a diameter of 4 metres , is dug to a depth of 14 metres . what is the volume of the earth dug out ? 
Options: a ) 32 m 3 , b ) 36 m 3 , c ) 40 m 3 , d ) 44 m 3 , e ) 176 m 3

Ex Output:
e


Ex Input:
Problem: the perimeter of a triangle is 36 cm and the in radius of the triangle is 2.5 cm . what is the area of the triangle ? 
Options: a ) 76 , b ) 88 , c ) 66 , d ) 55 , e ) 45

Ex Output:

e