You will be given a definition of a task first, then some input of the task.
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'.

Problem: in an examination , a pupil ' s average marks were 63 per paper . if he had obtained 20 more marks for his geography paper and 2 more marks for his history paper , his average per paper would have been 65 . how many papers were there in the examination ?
Options: a ) 8 , b ) 9 , c ) 10 , d ) 11 , e ) 12
Output:
d