The nature of the image formed on the retina of the human eye of an object is real and inverted.

Explanation:
Formation of Image in the Human Eye:
When light enters the eye through the cornea, it passes through the pupil and gets focused by the lens onto the retina. The retina is a layer of light-sensitive cells located at the back of the eye.

Real Image:
A real image is formed when light rays converge at a point after passing through a lens. In the human eye, the lens converges the incoming light rays onto the retina, forming a real image. This real image is formed due to the refraction of light by the lens.

Inverted Image:
The image formed on the retina is inverted, which means that the top of the object is projected onto the bottom of the retina, and the bottom of the object is projected onto the top of the retina. This inversion occurs because the lens refracts light in such a way that the rays cross over each other before reaching the retina.

Why is the Image Inverted?
The inversion of the image is a result of the way light rays interact with the lens. When light rays from an object pass through the convex lens of the eye, they refract or bend inward. The lens focuses the light rays to converge at a point on the retina, forming a real image. However, due to the nature of the lens, the light rays cross each other at this point, resulting in an inverted image.

Significance of Image Inversion:
Although the image formed on the retina is inverted, it is important to note that our brain processes this information and interprets the image correctly. The brain is able to understand the orientation of objects and perceive them as upright, despite the inverted image on the retina. This ability is known as visual perception and is a result of the brain's processing and interpretation of the incoming visual information.

In conclusion, the image formed on the retina of the human eye of an object is real and inverted. Although the image is inverted, our brain processes the information to perceive objects in the correct orientation.

The correct answer is (D)