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

Ex Input:
Problem: if an integer n is to be selected at random from 1 to 100 , inclusive , what is probability n ( n + 1 ) will be divisible by 5 ? 
Options: a ) 1 / 5 , b ) 1 / 3 , c ) 1 / 2 , d ) 2 / 3 , e ) 2 / 5

Ex Output:
e


Ex Input:
Problem: what is the next number : 2 , 17 , 257 , __ 
Options: a ) 2977 , b ) 3837 , c ) 4097 , d ) 4847 , e ) 5387

Ex Output:
c


Ex Input:
Problem: last year , for every 100 million vehicles that traveled on a certain highway , 40 vehicles were involved in accidents . if 2 billion vehicles traveled on the highway last year , how many of those vehicles were involved in accidents ? ( 1 billion = 1,000 , 000,000 ) 
Options: a ) 800 , b ) 900 , c ) 100 , d ) 1000 , e ) 950

Ex Output:

a