Correct option is B
In a concave mirror, when the object is placed at the centre of curvature, the image formed is real, inverted, and of the same size as the object. The image is also formed at the centre of curvature. This is a characteristic of the reflection of light rays in concave mirrors when the object is exactly at the centre of curvature.
If the object were placed at the focus, the image would be formed at infinity and would be much larger. If placed between the focus and centre of curvature, the image would be real, inverted, but enlarged.
Thus, the correct answer is (b) At the centre of curvature.
