Evaluate the effect of adding hydrochloric acid to a solution of calcium carbonate on its solubility.

• A. Solubility remains unchanged as calcium carbonate is insoluble.
• B. Solubility decreases due to the formation of calcium chloride.
• C. Solubility increases due to the formation of carbonic acid.
• D. Solubility decreases due to the common ion effect.

Answer: (C)