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'.

Example Input: Problem: in a simultaneous throw of a pair of dice , find the probability of getting a total more than 9 
Options: a ) 1 / 2 , b ) 7 / 18 , c ) 5 / 13 , d ) 5 / 12 , e ) 6 / 17
Example Output: b

Example Input: Problem: a high school has 400 students 1 / 2 attend the airthmetic club , 5 / 8 attend the biology club and 3 / 4 attend the chemistry club . 1 / 8 attend all 3 clubs . if every student attends at least one club how many students attend exactly 2 clubs . 
Options: a ) 300 , b ) 200 , c ) 250 , d ) 150 , e ) 160
Example Output: c

Example Input: Problem: in an election between two candidates a and b , the number of valid votes received by a exceeds those received by b by 15 % of the total number of votes polled . if 20 % of the votes polled were invalid and a total of 9720 votes were polled , then how many valid votes did b get ? 
Options: a ) 1888 , b ) 2999 , c ) 3159 , d ) 2777 , e ) 2991
Example Output:
c