Final answer:
Cave formations result from the dissolving of limestone bedrock by acid rain. This chemical reaction over long periods creates stalactites, stalagmites, and sinkholes, transforming the natural landscape.
Step-by-step explanation:
The formations seen in the cave are a result of acid rain dissolving soluble limestone bedrock. When groundwater containing atmospheric CO2 forms an acidic solution, it dissolves limestone (CaCO3) over thousands of years. As this CO2-rich water enters a cave and evaporates, it leaves behind supersaturated solutions where CaCO3 precipitates out to form stalactites and stalagmites. Additionally, sinkholes are formed from these reactions between acidic groundwaters and basic rock formations like limestone. The chemistry involved in cave and karst formations indicates that option C, acid rain dissolving limestone bedrock, is correct. These geological processes lead to the intricate and beautiful structures we can observe in various caves around the world.