At what distance in front of the concave mirror should an object be placed to get its virtual and erect image?

when an object is placed between the focus and pole of concave mirror the image is formed behind the concave mirror and is virtual, erect and enlarged. As shown in figure below.

Option (A): When object is kept at centre of curvature than image is formed at centre of curvature and is real, inverted. Therefore, Option A is incorrect.

Option (B): when an object is kept beyond centre of curvature the image formed is real, inverted and diminished. Therefore, Option B is incorrect.

Option (C): when an object is placed between focus and pole than image is virtual and erect as explained in explanation. Therefore, Option C is correct.

Option (D): when an object is placed at focus than image is formed at infinity and is real. Therefore, Option D is incorrect.