Southeast Asia Is Described as a "Geologically Active Zone," Meaning

Southeast Asia is described as a "geologically active zone," meaning that

A) it has open plains that are excellent for herding animals.
B) it has river valleys mixed with a warm dry climate, perfect for agriculture.
C) it has dry, rocky soil and heavy rainfall, which promote microorganisms.
D) the islands are the tops of a chain of volcanoes.
E) it suffers plate tectonic activity.