Based on your description, if you are located in the bottom row of a standard QWERTY keyboard and you reach to the right using your left pointer finger (L4), the letter you would key corresponds to the key that is directly right of your current position on the bottom row.
In the bottom row of the QWERTY keyboard, the letters are:
- Z (located at the left end)
- X
- C
- V
- B
- N
- M
If you are at the letter B (which is halfway on the bottom row) and you reach to the right, you would hit the letter N.
So the answer is N.