The correct answer is (a) Convex lens.
A myopic eye is an eye that can see objects that are close to it clearly, but objects that are far away appear blurry. This is because the light rays from distant objects are focused in front of the retina, instead of on the retina. A convex lens can correct this problem by bending the light rays so that they focus on the retina.
A concave lens is a lens that curves inward, like the inside of a bowl. It bends light rays away from each other, which makes objects appear smaller. A cylindrical lens is a lens that has different curvatures in different directions. It is used to correct astigmatism, which is a condition in which the cornea is not perfectly round. A plane convex lens is a lens that has one flat surface and one curved surface. It is not used to correct myopia.