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: a & b started a partnership business . a ' s investment was thrice the investment of b and the period of his investment was two times the period of investments of b . if b received rs 5000 as profit , what is their total profit ?
Options: a ) 28000 , b ) 30000 , c ) 32000 , d ) 35000 , e ) none of these
Example Output: d

Example Input: Problem: a number is doubled and 6 is added . if resultant is trebled , it becomes 72 . what is that number
Options: a ) 8 , b ) 10 , c ) 9 , d ) 14 , e ) 16
Example Output: c

Example Input: Problem: rahim bought 65 books for rs . 1150 from one shop and 50 books for rs . 920 from another . what is the average price he paid per book ?
Options: a ) rs . 17 , b ) rs . 18 , c ) rs . 12 , d ) rs . 11 , e ) rs . 10
Example Output:
b