A concave mirror is placed on a horizontal table with its axis directed vertically upwards. Let \[O\]be the pole of the mirror and\[C\] its centre of curvature. A point object is placed at \[C.\] It has a real image, also located at \[C.\] If the mirror is now filled with water, the image will be [IIT-JEE 1998]

• A.            Real, and will remain at C
• B.            Real, and located at a point between C and \[\infty \]
• C.            Virtual and located at a point between C and O
• D.            Real, and located at a point between C and O