Correct Response: C. Guyots are the submerged and eroded remnants of volcanoes that originally grew up from the ocean floor to build above the ocean surface. As ocean volcanoes become inactive and cool they slowly sink into the oceanic crust. The evidence suggests that guyots start out as isolated volcanoes that grew above the ocean surface and then slowly sank. During the first stages of subsidence, fringing reefs develop around them. With continued subsidence, they become coral atolls and, finally with continued subsidence, they become entirely submerged flat-topped seamounts. Although reefs grow around guyots (A), guyots are not formed through the growth of coral reefs. As they are primarily composed of volcanic rock, guyots are not accumulations of marine diatoms (B). Tectonic plate fragments are typically uplifted at active plate margins and not within oceanic plates (D) and so are not associated with guyot formation.