Task: Question Answering
Input (English): Problem: a cistern is two - third full of water . pipe a can fill the remaining part in 12 minutes and pipe b in 8 minutes . once the cistern is emptied , how much time will they take to fill it together completely ? 
Options: a ) 12 minutes , b ) 12.5 min , c ) 14.4 min , d ) 10.2 min , e ) 14.66 min
Output (English): c