To find the correct mirror image of the given figure when the mirror is placed at MN, we must understand that the mirror image will be a lateral inversion of the original figure. This means that the left and right parts of the image will be reversed.

Here is the image under consideration:

Let’s consider each step:

1. The first letter 'a' in the original figure will appear on the far right in the mirror image.
2. The letters will appear in the reverse order when reflected over the mirror.
3. Special attention should be paid to letters with asymmetrical shapes, like 'R' and 'N', as their direction will also be inverted.

Now, let’s evaluate the options:

• 

  - This option correctly shows the letters in order from right to left, and each letter is the correct mirror image.

• 

  - This option does not reverse the letters, so it is incorrect.

• 

  - Some letters are incorrectly inverted.

• 

  - This option has incorrectly arranged letters.

Based on the evaluation, the correct mirror image is:

Therefore, the correct answer is the first option.