Task: Question Answering
Input (English): Problem: a rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered . if the area of the field is 400 sq . ft , how many feet of fencing will be required ? 
Options: a ) 60 feet , b ) 50 feet , c ) 40 feet , d ) 30 feet , e ) 5 feet
Output (English): a