Task: Question Answering
Input (English): Problem: a person decided to build a house in 100 days . he employed 100 men in the beginning and 100 more after 20 days and completed the construction in stipulated time . if he had not employed the additional men , how many days behind schedule would it have been finished ? 
Options: a ) 40 , b ) 80 , c ) 70 , d ) 60 , e ) 50
Output (English): b