Which of the following pair of position of object - position of image - size of image, of image is NOT correct for concave mirror?

At infinity - At C - Highly diminished

The correct answer is option 4. At infinity - At C - Highly diminished.

In a concave mirror, when the object is located at infinity, the image is formed at the focus (F). The size of the image in this case is highly diminished. This is because parallel rays from the object converge at the focus after reflection, resulting in a small, highly diminished image. Therefore, the given pair is not correct for a concave mirror.