Task: Question Answering
Input (English): Problem: if 15 men , working 9 hours a day , can reap a field in 16 days , in how many days will 18 men reap the field , working 8 hours a day ? 
Options: a ) 10 , b ) 15 , c ) 20 , d ) 25 , e ) none of them
Output (English): b