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: 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
Example Output: b

Example Input: Problem: a number whose fifth part increased by 7 is equal to its fourth part diminished by 7 is ? 
Options: a ) 160 , b ) 180 , c ) 200 , d ) 280 , e ) none
Example Output: d

Example Input: Problem: what is the positive difference between the sum of the squares of the first 8 positive integers and the sum of the prime numbers between the first square and fourth square ? 
Options: a ) 161 , b ) 162 , c ) 163 , d ) 164 , e ) 165
Example Output:
c