The correct answer is D. Mountains.
Step-by-step explanation
Mountain is the name given to the geo forms or natural elevations of the earth's crust that have a minimum height of 700 meters, and therefore are higher than other lower formations such as hills. The mountains are the result of a geological process called orogenesis, in which the crust bends from the lateral thrust of the tectonic plates. The mountains occupy about 25% of the earth's surface. In general, rivers originate at the tops of the mountains, because at heights above 4000 meters there are moor areas where water from the clouds condenses and forms the rivers or snowfalls that melt and form rivers. The mountains also host large cities and towns because there is a variety of different climates and conditions for agriculture. So, the correct answer is Mountains.