Task: Question Answering
Input (English): Question: A and B can do a piece of work in 7 days, B and C in 8 days, C and A in 9 days. How long will C take to do it?

 Option A: 14.1 days

 Option B: 18.8 days

 Option C: 21.4 days

 Option D: 24.3 days

 Option E: 26.5 days
Output (English): Option C