Which of the following best explains how a tephra deposit forms?

a. highly fluid lava erupts from an active volcano and flows across great distances, slowly solidifying into a flat surface.
b. as magma is forced upward, it travels horizontally through cracks in the crust, solidifying into either long, horizontal shafts or saucer-shaped formations.
c. airborne ash and rocks from a volcanic eruption remain suspended in the air for a long time before eventually settling to the ground in a new location far from the volcano.
d. as magma is forced upward, it travels through vertical cracks in the crust, spreading outward and pushing up an overlying layer, creating a do