Answer:
D. Volcanoes erupt when the crust is moved by the convection of Earth's inner and outer cores.
Step-by-step explanation:
The solid crust of Earth serves as a heat insulator for the planet's warm interior. The molten rock in the mantle, below the crust, is known as magma. Convection currents are created by the intense heat and pressure that exists within the earth. The tectonic plates that make up the earth's crust shift as a result of these currents.