According to the article about Mt. Pinatubo's eruption , what caused thousands of roofs to collapse ?

A. The eruption triggered an earthquake , which caused roofs to collapse .

B. The violent shaking of the eruption caused roofs to collapse .

C. The ash mixed with the typhoon's rain became too heavy for roofs to support .

D. The eruption spewed out large rocks , which landed on roofs and caused them to collapse .​