The melted rock that forms a volcano is called

The melted rock that forms a volcano is called magma.
Magma is present beneath the earth's surface and when the magma is cooled to form a solid than it is known as igneous rock, we consider the lava as a type of this so we can say that when magma reaches the surface of earth than it becomes lava. The reason behind the occurrence of volcanoes is the movement of plates of earth.

Alpha particles have positive charge, beta particles have negative charge, and answer 4 just doesn’t make sense. thus, you are left with only one possible answer.