Closed contours, with higher value inwards, represent a A. depression B. hillock C. plain surface D. none of the above

The correct answer is: A. depression.

Closed contours, with higher value inwards, represent a depression. This is because the contour lines are closer together in a depression, which indicates that the land is lower in that area.

A hillock is a small hill, and a plain surface is a flat surface. Neither of these would have closed contours with higher value inwards.