As Magma Approaches the Surface, Water Contributes to the Explosive

As magma approaches the surface, water contributes to the explosive potential of the eruption because _______ .

A) water has a lower density in its solid phase than its liquid phase which makes it explode when pressure decreases
B) water dissolved in magma flashes to steam as pressure decreases, and the volume increase leads to an explosive potential
C) water dissociates to hydrogen and oxygen at high temperatures but reacts violently at decreasing pressures to produce explosive eruptions
D) water has a large heat capacity, which allow it to keep the magma hot enough to explode