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 z is not equal to zero , and z = 6 zs − 9 s 2 − − − − − − − − √ z = 6 zs − 9 s 2 , then z equals : 
Options: a ) s , b ) 3 s , c ) 4 s , d ) - 3 s , e ) - 4 s

Ex Output:
b


Ex Input:
Problem: solution x is 10 percent alcohol by volume , and solution y is 30 percent alcohol by volume . how many milliliters of solution y must be added to 150 milliliters of solution x to create a solution that is 25 percent alcohol by volume ? 
Options: a ) 250 / 3 , b ) 500 / 3 , c ) 400 , d ) 450 , e ) 600

Ex Output:
d


Ex Input:
Problem: find a positive number which when increased by 17 is equal to 60 times the reciprocal of the number 
Options: a ) 17 , b ) 15 , c ) 12 , d ) 8 , e ) 3

Ex Output:

e