Topographic maps are used to measure a-composition b-movement c-elevation d-texture

Topographic maps are used to measure the elevation.

Explanation:

A topographic map is a two-dimensional representation of an area or a region in which the differences in the elevation of the terrain are shown with the help of contour lines. These contour lines pass through points of the same elevation giving a brief idea of the geographical undulations and features in the region. Topographic maps are generally used for geological mapping of different terrains.

Exposed great deposits of coal and iron ore