the answer is D
"During convection, heat is being transferred between substances in direct contact with each other by electro magnetic waves."
"Using the molten rock to explain the convection in the earth relative to how if affects the weather condition. Here, the rock is in a molten state, rising up from the bottom of the mantle after becoming hotter and less dense from the heat of the earth's core. As the rock loses heat into the earth's crust, it become cooler and more dense,sinking back to the core. These constantly circulating cells of hotter and cooler molten rock help to heat the earth's surface."