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 center 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.

• A. real, and will remain at C.
• B. real, and located at a point between C and O.
• C. virtual, and located at a point between C and O
• D. real, and located at a point between C and O