Answer:
The Answer is: A. Pyroclastic flow
Explanation: Pyroclastic flows are high-density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at high speeds. They may result from the explosive eruption of molten or solid rock fragments, or both.
courtesy: https://courses.lumenlearning.com/geo/chapter/reading-volcanic-gases-pyroclastic-flow-and-tephra/
