Task: Question Answering
Input (English): Question: Five drainage pipes, each draining water from a pool at the same constant rate, together can drain a certain pool in 12 days. How many additional pipes V, each draining water at the same constant rate, will be needed to drain the pool in 4 days?

 Option A:  6

 Option B:  9

 Option C:  10

 Option D:  12

 Option E:  15
Output (English): Option C