Task: Question Answering
Input (English): Problem: a student was asked to find 4 / 5 of a number . but the student divided the number by 4 / 5 , thus the student got 9 more than the correct answer . find the number . 
Options: a ) 16 , b ) 18 , c ) 20 , d ) 22 , e ) 24
Output (English): c