Answer: A
Step-by-step explanation:
From the figure given as attachments, the error pointing upward signifies the incident ray while the one point downwards signifies the reflected ray.
One of the laws of reflection is stated that the angle of incidence is equal to the angle of reflection.
Since the two arrows are parallel to each other, then the mirror must be perpendicular to the two arrows. That is, the incident ray and the reflected ray must be perpendicular to the mirror.
Option A is the correct answer.