Task: Question Answering
Input (English): Problem: a and b finish the job in 15 days . while a , b and c can finish it in 5 days . c alone will finish the job in 
Options: a ) 4.50 days , b ) 3.50 days , c ) 6.0 days , d ) 7.5 days , e ) 5.50 days
Output (English): d