Answer: Option C
Answer: (c)
Karst topography, a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum, characterized by underground drainage systems with sinkholes and caves. A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer.
They are common where the rock below the land surface is limestone or other carbonate rock, that can be dissolved naturally by circulating groundwater.