Task: Question Answering
Input (English): Problem: it takes avery 3 hours to build a brick wall while tom can do it in 4 hours . if the two start working together and after an hour avery leaves , how much time will it take tom to complete the wall on his own ? 
Options: a ) 25 minutes . , b ) 55 minutes . , c ) 1 hour and 41 minutes , d ) 1 hour and 35 minutes , e ) 1 hour and 20 minutes
Output (English): c