Task: Question Answering
Input (English): Question: Tony alone can paint a wall in 7 days and his friend Roy alone can paint the same wall in 9 days. In how many days they can paint the wall working together? Round off the answer to the nearest integer.

 Option A: 2

 Option B: 4

 Option C: 6

 Option D: 7

 Option E: 9
Output (English): Option B