Hey there! Hello!
Let's get right to it: the pupil is the black part of eye in the center of the iris and gets larger and smaller depending on the lighting situation of the environment.
The cornea is the transparent coating that goes over the whole eye.
The retina is located in the back of the eye and is the part that makes your eyes sensitive to light and triggers nerve impulses that go back to the brain.
Finally, the iris is the colored part around the pupil. In terms of your question, the answer will be D.
Hope this helped you out! Feel free to ask any additional questions if you have any. :-)
