(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.