The correct answer is B. Lava flows, pyroclasts.
Step-by-step explanation
A volcano is a mountain or hill that has an opening through which gaseous, liquid or solid materials can escape from the interior of the Earth. At the top of this cone, there is a concave formation called crater or chimney. When activity occurs in a volcano it is because it is erupting. Also, when it is erupting, the molten rock that comes from the Earth's mantle, known as magma, comes out. Once the magma comes to the surface, it loses the gases it contains because it evaporates, and when it drains the slopes of the cone it is known as lava, which flows from the top of the volcano. Finally, the waste expelled by a volcano through its crater during an eruption is known as pyroclasts. So, the correct answer is B. Lava flows, pyroclasts.