Select the correct mirror image of the given alphanumeric string when a vertical mirror is placed at the line $MN$ on its right side:

When a vertical mirror is placed on the right side of a string, lateral inversion occurs. The order of characters is completely reversed from right to left, and each individual letter/number is flipped horizontally:
1. f (the right-most character) appears first on the left, horizontally flipped.
2. e appears second, horizontally flipped.
3. A appears third; since it is horizontally symmetric, it looks unchanged.
4. 7 appears fourth, horizontally flipped.
5. 2 appears fifth, horizontally flipped.
6. L (the left-most character) appears last on the right, horizontally flipped.

This accurate transformation corresponds precisely to the layout shown in Figure 4.