Closed contours of decreasing values towards their centre, represent

ANS:B - a depression

Closed contours of decreasing value towards centre indicates a depression.
Closed contours of increasing value towards centre indicates a hill. Increasing value towards there center indicates hill and in a ridge line concave side of higher values inside indicates ridge line and higher values upward indicates valley. A series of closed contour line on the map indicate the depression when the higher values are outside, while the series of closed contour lines on the map indicates the hill when the higher values are inside. The centre of the depression is in a lower altitude and the sides of the valley in height. So the correct answer is B.