Task: Question Answering
Input (English): Problem: a can do a piece of work in 4 hours ; b and c together can do it in 3 hours , while a and c together can do it 2 hours . how long will b alone take to do it ? 
Options: a ) 8 hours , b ) 10 hours , c ) 12 hours , d ) 24 hours , e ) none of these
Output (English): c