Task: Question Answering
Input (English): Problem: the average mark of the students of a class in a particular exam is 90 . if 2 students whose average mark in that exam is 45 are excluded , the average mark of the remaining will be 95 . find the number of students who wrote the exam ? 
Options: a ) 10 , b ) 40 , c ) 20 , d ) 30 , e ) 25
Output (English): c