Select the correct answer. What causes magma in the lower mantle of Earth to rise up toward the crust? A. The moon's gravitational force acts on the magma. B. The core of Earth expands. C. The density of the magma decreases. D. The volume of the magma decreases.

Option A, The density of the magma decreases.

Explanation:

The mantle of the earth crust melts when the oceanic plate descends into the mantle. The density of this mantle is quite lower than the surrounding rocks and thus it rises upto the surface of earth to form a volcano. However, the pressure beneath the earth crust enables magma to break the rock and gush out of the cracks

the answer to your question is c. the density of the magma decreases, your welcome.