The correct answer is (d). Infinite images will be formed if a point light source is placed between two parallel plane mirrors.
The image formed by a plane mirror is always virtual, upright, and of the same size as the object. The image is located behind the mirror at the same distance from the mirror as the object is in front of the mirror.
If a point light source is placed between two parallel plane mirrors, the light rays from the source will reflect off of both mirrors and form an infinite number of images. The images will be arranged in a straight line between the two mirrors, with the first image being the same size as the object and the subsequent images getting smaller and smaller.
The following diagram shows the formation of images of a point light source placed between two parallel plane mirrors:
[Diagram of a point light source placed between two parallel plane mirrors, with the light rays reflecting off of both mirrors and forming an infinite number of images]
The first image is formed by the light rays reflecting off of the two mirrors and meeting at a point behind the mirror. The second image is formed by the light rays reflecting off of the two mirrors and meeting at a point in front of the first image. The third image is formed by the light rays reflecting off of the two mirrors and meeting at a point in front of the second image, and so on.
The images will continue to get smaller and smaller as they get further away from the object. The images will also be fainter and fainter, as the light rays are spread out over a larger area.
In practice, the images will be so small and faint that they will not be visible to the naked eye. However, they can be seen using a camera or other optical instrument.