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: ( 51 + 52 + 53 + … … … + 100 ) is equal to : 
Options: a ) 2525 , b ) 2975 , c ) 3225 , d ) 3775 , e ) 3885
Example Output: d

Example Input: Problem: a person spends 1 / 3 rd of the money with him on clothes , 1 / 5 th of the remaining on food and 1 / 4 th of the remaining on travel . now , he is left with rs 300 . how much did he have with him in the beginning ? 
Options: a ) s 200 , b ) s 750 , c ) s 300 , d ) s 450 , e ) s 550
Example Output: b

Example Input: Problem: a , b and c started a business with a total investment of rs . 72000 . a invests rs . 6000 more than b and b invests rs . 3000 less than c . if the total profit at the end of a year is rs . 8640 , find b ' s share . 
Options: a ) rs . 3240 , b ) rs . 2520 , c ) rs . 2880 , d ) rs . 3360 , e ) none of these
Example Output:
b