An object shaped as $L$ is placed between two parallel plane mirrors as shown. In the first seven closest images, how many laterally inverted images are formed?

The correct option is D $4$
Since the mirrors are parallel the number of images formed are infinite. We are talking about the first $7$ images. The first two will be laterally inverted and the next two will be inverted of laterally inverted hence same as object (not laterally inverted) next two should be laterally inverted. Last one must be inverted of laterally inverted hence same as object (not laterally inverted. )Therefore, $4$ are laterally inverted out of $7$.

Hence, Option $D$ is the correct answer.