Explanation:
When an object is placed in front of a plane mirror, the image formed is virtual and erect. This means that the image is not a real image, but a virtual one that cannot be projected onto a screen. The image also appears upright and in the same orientation as the object.

Virtual Image:
A virtual image is one that cannot be formed on a screen. It is formed by the apparent intersection of the reflected rays in the mirror. In the case of a plane mirror, the rays of light reflect off the mirror surface and appear to come from behind the mirror. This creates the illusion of an image being formed behind the mirror, even though no actual rays are converging at that point.

Erect Image:
An erect image is one that appears in the same orientation as the object. In the case of a plane mirror, the image is not flipped or inverted. If you raise your right hand in front of a plane mirror, the image in the mirror will also show a right hand.

Real Image:
A real image is one that can be formed on a screen. It is formed by the actual convergence of light rays at a specific point. This is different from a virtual image, which cannot be projected onto a screen.

Inverted Image:
An inverted image is one that appears upside down compared to the object. This occurs when the light rays cross each other before reaching the image. In the case of a plane mirror, the light rays do not cross each other, so the image is not inverted.

Conclusion:
Based on the characteristics of a plane mirror, the correct answer is option D - the image formed in a plane mirror is virtual and erect.