Answer:
B. the sudden release of accumulated gas pressure blasts the lava upward, forming pyroclastic debris.
Explanation:
Lava flows occurs in non explosive eruptions. This is because it is favored by low gas and low viscosity which brings fire fountain when the gases dissolves. For explosive eruptions, the pressure blast the lava upwards forming debris instead. So when this happens, it sends ash, gas and magma high up into the atmosphere. These eruptions occurs when sufficient gas has dissolved under pressure within a viscous magma in such a way that the lava is expelled violently froths into volcanic ash when pressure is suddenly lowered at the vent.
