Task: Question Answering
Input (English): Problem: a can do a piece of work in 20 days , b can do a piece of work in 12 days , both are working together for 3 days after a left the job , then how many days b requires to complete the remaining work ? 
Options: a ) 6 days , b ) 5 days , c ) 3 days , d ) 7 days , e ) 12 days
Output (English): c