The picture shows rays passing through an unknown lens. which ray would appear on a ray diagram for both a concave lens and a convex lens? a b c d

it id D because it is directed at the middle of the lens so it will be the same

The center point of a lens is called its optical center. According to convention, when the ray of light is parallel to the principal axis, it will pass through the focus and vice versa. Also, when the ray passes through the optical center it will go undeviated.

A ray of light when passes through the optical center of any lens will emerge without any deviation. In case of concave lens, ray D will emerge out.

Similarly, in case of convex lens ray D will emerge out.

So, in either type of lens ray D will emerge out.

there are no contact forces mentioned on the list of choices that you've provided.