Answer:
A. at the focal point of the lens.
Step-by-step explanation:
The lens is a device of a certain type of curvature that bends light causing optical phenomena. The focal point of a lens or focus is the point where rays converges in a convex lens or diverges from in a concave lens.
The convex lens concentrates the rays to a point, whereas in a concave lens the rays diverge from a point. The point on the principal axis is called focal point or focus.
Hence, the answer is A. at the focal point of the lens.