In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: two passenger trains start at the same hour in the day from two different stations and move towards each other at the rate of 22 kmph and 21 kmph respectively . when they meet , it is found that one train has traveled 60 km more than the other one . the distance between the two stations is ? 
Options: a ) 288 , b ) 516 , c ) 877 , d ) 278 , e ) 178

Ex Output:
b


Ex Input:
Problem: find the length of the wire required to go 15 times round a square field containing 69696 m 2 . 
Options: a ) 15840 , b ) 15848 , c ) 15828 , d ) 27892 , e ) 22892

Ex Output:
a


Ex Input:
Problem: 2 a 33 + b 9 ____ 99 if a and b represent positive single digits in the correctly worked computation above , what is the value of a + 3 b ? 
Options: a ) 2 , b ) 7 , c ) 9 , d ) 11 , e ) 12

Ex Output:

d