Short sightedness in humans can be corrected by using
(A) Concave lens
(B) Convex lens
(C) Cylindrical lens
(D) Plain glass

Hint :In order to solve this question, we are going to first see and tell what the problem of short sightedness means. How technically it affects the vision of the person and how that effect on the vision can be reduced or in other words can be corrected to make the vision clearer.

Complete Step By Step Answer:
The short sightedness in human beings is also known as Myopia. It is referred to as the inability of a person to see far off objects clearly. The person can have a clear vision of objects up to a short distance only. In this problem, the image is formed before the retina. In order to move the image to a position where it should lie, like for a normal eye, a type of lens is used. These lenses form the image of the image formed before the retina acting as the object at the position for a normal eye.
The type of lenses that are used in this are concave lenses.
Hence, option (A) Concave lens is the correct answer.

Note :
The concave lenses are that type of lens which are curved inwards. This structure adds to the treatment of short sightedness. They are placed in front of a myopic eye and they move the image back to the retina and make it clearer. Hence, giving the clear vision of the far off objects to the person.