Task: Question Answering
Input (English): Problem: a , b and c can do a piece of work in 24 , 30 and 40 days respectively . they start the work together but c leaves 4 days before the completion of the work . in how many days is the work done ? 
Options: a ) 11 , b ) 5 , c ) 70 , d ) 11 , e ) 13
Output (English): d