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: 16.02 ã — 0.01 = ? 
Options: a ) 0.1602 , b ) 0.001602 , c ) 1.6021 , d ) 0.01602 , e ) none of these
Example Output: a

Example Input: Problem: what is the next number 12 13 15 17 111 113 117 119 123 129 ? 
Options: a ) 154 , b ) 220 , c ) 129 , d ) 131 , e ) 224
Example Output: d

Example Input: Problem: calculate the value of n from the below equation : n ^ 3 â ˆ ’ 10 n + 20 = 44 
Options: a ) 1 , b ) 5 , c ) 3 , d ) 2 , e ) 4
Example Output:
e