Task: Question Answering
Input (English): Question: David completes a piece of work in 5 days, John completes the same work in 9 days. If both of them work together, then the number of days required to complete the work is?

 Option A: 3.2 days

 Option B: 8 days

 Option C: 10 days

 Option D: 12 days

 Option E: 14 days
Output (English): Option A