**Concept:** The question tests on the basics of Counting

**Solution:**

Probability = Favourable Outcomes / Total Outcomes

The first department can send a file in 3 ways

Similarly the 2nd , 3rd and 4th department each can send a file in 3 ways each.

Therefore Total outcomes = 3434

Favourable Outcomes: Assume the 1st typist gets 1 file, the second gets 1 of the remaining 3 files and the 3rd typist gets the last 2 files.

This is 4C1 * 3C1 * 2C2 = 4 * 3 * 1 = 12

This distribution can be done in 3 ways (1, 1, 2) (1, 2, 1) and (2, 1,1). So total favorable outcomes = 12 * 3 = 36

The required probability = 36/81 = 4/9**Option C**