The type of heat transfer that causes the air to circulate and form such clouds is called (option D) CONVECTION.
Convection refers to the process by which the heat energy transfers by circulation of liquids or gases. In the atmosphere, when the air is heated, the air molecules expand becoming less dense; as a result the less dense molecules rise. When it is cool, the air becomes dense and sinks; so it pushes warm air up where it expands once more. The cool air sinks again as it becomes denser; then it is warmed by the Earth's surface and the process starts again. The convection current creates an ongoing cycle of warming, rising, cooling and sinking.
