The magma is heated and becomes less dense by the core moving it toward the crust.
Option D.
Step-by-step explanation:
Magma is a form of molten rock which might be partially molten or might be fully molten. Magma consists of silicate liquid.
This molten part of the rock is either ejected in the form of lava or this molten rock might move from upper layer of Earth to the lower layer of Earth. The crystals which are not molten which get transported into the magma, form bubbles and get separated.