Final answer:
The correct option is A. When a concave mirror and a convex mirror face each other, the main property observed is image formation. A concave mirror can form real and inverted images when the object is placed on the far side of the focal point, while a convex mirror always forms virtual, upright, and smaller images.
Step-by-step explanation:
A concave mirror and a convex mirror are facing each other. When two mirrors face each other, they can create multiple images due to the reflection and convergence of light rays. The image formation is the main property observed in this setup. In the case of a concave mirror, the image formed depends on the position of the object relative to the focal point of the mirror.
For objects placed on the far side of the focal point, a real and inverted image is formed. For objects placed between the focal point and the mirror, a virtual and upright image is formed. On the other hand, a convex mirror always forms virtual, upright, and smaller images.