(a) When the object is kept at a distance equal to its radius of curvature
(b) When an object is kept at a distance less than its focal length
(c) When an object is placed between the focus and centre of curvature
(d) When an object is kept at a distance greater than its radius of curvature
Answer: (c) When an object is placed between the focus and centre of curvature
Explanation: When an object is placed between the focus and centre of curvature, the concave mirror can form an image larger than the actual object.