Most oceanic islands and seamounts are:

A) small pieces rifted apart from continents
B) places where the seafloor has been buckled upward by convergence
C) constructed by volcanic eruptions that first occur under water
D) large fan-shaped mounds deposited by turbidity currents

Seamounts

Submerged mountain ranges or isolated peaks formed by volcanic activity beneath the ocean surface, often rising several thousand feet from the seabed.

Volcanic Eruptions

The process where magma, ash, and gases are expelled from a volcano, significantly impacting the surrounding environment.