To determine the correct mirror image of the given figure when the mirror is placed at MN, follow these logical steps:

1. Identify the original figure's orientation and key features, such as shapes and their positions relative to the mirror line (MN).
2. Understand that a mirror image is essentially a reflection of the original, which means any points on one side of the mirror equidistant will appear similarly on the opposite side in the reflection.
3. Examine all options provided and focus on the horizontal symmetry around the MN line because it acts as the mirror. The parts of the image that are closest to the mirror remain closest in the mirrored version, while symmetry ensures flipped relative positions.
4. Carefully match each detail in the options provided to see which one shows the same features in their mirrored positions.

After analyzing the options, the correct mirror image of the given figure is: