The lens within an eye focuses light onto the
a. pupil.
b. cornea.
c. retina.
d. iris

The correct answer is C) Retina.

The light enters eye through pupil ( a small black colored hole in the center of iris of the eye). The light is focussed onto retina ( a sensory membrane located at the back of the eye) with the help of cornea and eye lens.

Photoreceptor cells are present in the retina that converts the incoming light into electrical signals, which are finally sent to brain via optic nerve in order to from the visual image.