Concept:Karst landforms such as stalactites, swallow holes, and caverns are created by the chemical weathering of soluble carbonate rocks.
Explanation:These features belong to karst topography, which develops mainly over limestone.
Rainwater mixed with carbon dioxide becomes mildly acidic.
This acidic water slowly dissolves the limestone, forming underground caves and caverns.
Stalactites hang from cave ceilings as dissolved minerals re-deposit.
Swallow holes are surface openings where water disappears into the underground drainage system.
Therefore, such features are found only in limestone regions.
Answer:D. Limestone regions