In human eyes, the image of the object forms on :

• In human eyes, the lens focuses light on the back of the eye, on a layer called the retina. The image of the objects is formed on the retina. 
• It contains several nerve cells that are sensitive to light and colours. Sensations felt by these nerve cells in the retina are then transmitted to the brain through the optic nerve.

Therefore, Retina is the correct answer.