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: how many integers between 1 and 10 ^ 16 are such that the sum of their digits is 2 ? 
Options: a ) 106 , b ) 116 , c ) 126 , d ) 136 , e ) 146
Example Output: d

Example Input: Problem: 20.20 / 2000 is equal to : 
Options: a ) 1.01252677 , b ) 0.013466667 , c ) 0.125266677 , d ) 0.126256677 , e ) 0.12725776
Example Output: b

Example Input: Problem: 1504 x 1504 = ? 
Options: a ) 2262016 , b ) 2250000 , c ) 12000 , d ) 2262000 , e ) 2250016
Example Output:
a