When two plane mirrors are placed parallel and facing each other, and an object is kept in between them, we get infinite images. But actually, only a few images are visible because the intensity of the image is:

The correct option is B

decreased after each reflection

Even after the formation of infinite images, only a few images are visible because

1. Some amount of light gets absorbed by mirrors after each reflection.
2. Thus, the intensity of the image is decreased after subsequent reflection.
3. So, images keep on getting dimmer and get invisible later.

Hence, the correct option is (B).