Lava and other materials that are launched from a volcano into the air are referred to as tephra. The correct option among all the options given in the question is option "A".Tephra is actually the material that is ejected by an active
volcano irrespective of the type of the material, fragment size or emplacement
mechanism. The airborne substances of the volcanoes are known by the name
pyroclasts. The pyroclasts remain as tephra unless they become hot enough to
fuse together.
