B

Step 1: Understand the setup of the problem. The height of the mirror is 1 m and the man is standing 2 m away from the mirror.
Step 2: Identify the distances:
- Distance from the man to the mirror = 2 m
- Distance from the mirror to the wall = 4 m
Step 3: The total distance from the man to the wall where the mirror reflects the image = 2 m + 4 m = 6 m.
Step 4: Since the mirror is 1 m high, the man can see the image reflected at the same height due to light reflection principles.
Step 5: For the portion of the wall that can be seen, we can use similar triangles: the height of the reflected image from the man's eyes to the wall will be proportional to the distances involved.
Step 6: The proportion of height increase is determined by the distance ratios: If the man's line of sight down to the mirror reflects up to the wall, the visible height will scale with respect to those distances.
Step 7: Since the total line length is effectively doubled from 2 + 4 = 6 m, the height can also be noted as doubling the height of the mirror with respect to the angles formed in each triangle created by the mirror and the observer.
Step 8: Therefore, the height of the wall portion visible is height of mirror plus additional scaling into the distance, which is effectively mirrored as the observer is 6 m away and still able to see the 1 m height.
So effectively, the wall portion viewable would result to still remain at a 1 m height as the focal points remain aligned from point of viewing.
Therefore, the visible height of the portion of the opposite wall is effectively 1m reflected at position which means the answer height can be stated at respective positions due to reflections.