Which of the following features is formed by the collapse of caves?

A) travertine
B) stalagmite
C) stalactite
D) sinkhole
E) flowstone

Caves Collapse

The sudden failure and falling in of a cave's ceiling or walls, often due to natural processes such as erosion or the removal of supporting material.

Sinkhole

A depression or hole in the ground caused by the collapse of a surface layer, often due to the dissolution of limestone or other carbonate rock by groundwater.