Where is the cornea located?

The cornea is indeed located at the anterior portion of the sclera. The sclera, which is the white outer layer of the eyeball, provides structure and protection. The cornea itself is a transparent, dome-shaped surface that covers the front of the eye, allowing light to enter and contributing to the eye's overall refractive ability. Its position as the most anterior part of the eye and its direct interaction with external light sources make option A the correct choice.

The other options refer to different anatomical components of the eye. The posterior segment comprises structures like the vitreous body and retina, which are located at the back of the eye and are not where the cornea is found. The inner layer of the eye primarily refers to the choroid, retina, and other internal structures that do not include the cornea. Finally, the optic nerve is responsible for transmitting visual information from the retina to the brain but is not part of the eye's structural anatomy like the cornea.