Task: Question Answering
Input (English): Question: P can lay railway track between two stations in 16 days. Q can do the same job in 12 days. With the help of R, they completes the job in 4 days. How much days does it take for R alone to complete the work?

 Option A: 2/7

 Option B: 4/9

 Option C: 6/7

 Option D: 1/2

 Option E: 9 3/5
Output (English): Option E