It Is Difficult for Scientists to Understand the Evolution of Ancient

It is difficult for scientists to understand the evolution of ancient volcanoes (stratovolcanoes) . Many times researchers can determine the degree of explosiveness and the height of the eruption column by studying the size of pyroclastic material and the distance they travelled. It can be inferred that the larger the fragments erupted, the more explosive the eruption; the more explosive the eruption, the farther the distance volcanic fragments travel; and:

A) the thinner the ash deposits, the longer the duration
B) the farther pyroclastic material travel, the higher the eruption column
C) the thicker the pyroclastic deposit, the smaller the eruption column
D) the higher the volume of pyroclastic material erupted, the shorter the duration