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: the average of 13 numbers is 60 . average of the first 7 of them is 57 and that of the last 7 is 61 . find the 8 th number ? 
Options: a ) 43 , b ) 30 , c ) 35 , d ) 45 , e ) 50
Example Output: a

Example Input: Problem: how many positive integers less than 1000 are multiples of 5 but not of 4 or 7 ? 
Options: a ) 114 , b ) 121 , c ) 122 , d ) 129 , e ) 136
Example Output: c

Example Input: Problem: if the average ( arithmetic mean ) of a and b is 140 , and the average of b and c is 100 , what is the value of a − c ? 
Options: a ) − 220 , b ) − 100 , c ) 100 , d ) 135 , e ) 80
Example Output:
e