They may show many things like rivers, oceans, county boundaries, and yes even rocks and mountains
They make up the middle east, or what was the center of the muslim world during the middle ages
I'm going to say C. i'm not 100% sure but its the most reliable
They helped cool off the earth removing heat from its interior. Volcanic emissions have produced the atmosphere and the water of the oceans. Volcanoes make islands and add to the continents. Volcanic deposits are also used as building materials.