The correct answer is (b). A concave lens is used to correct myopia, also known as nearsightedness. Myopia is a condition in which a person can see objects that are close to them clearly, but objects that are far away appear blurry. A concave lens is a lens that curves inward, like the inside of a bowl. When light passes through a concave lens, it is spread out, which helps to correct the vision of a person with myopia.
A convex lens is a lens that curves outward, like the outside of a ball. When light passes through a convex lens, it is focused, which helps to correct the vision of a person with farsightedness.
A cylindrical lens is a lens that has one curved surface and one flat surface. Cylindrical lenses are used to correct astigmatism, a condition in which the cornea is not perfectly round. Astigmatism can cause blurred vision, both near and far.
I hope this helps!