A protein undergoes hydroxylation. What is the impact of this modification on the protein's structure?

• A. It adds a lipid group, anchoring the protein to membranes.
• B. It removes a phosphate group, decreasing the protein's activity.
• C. It introduces a hydroxyl group, potentially increasing the protein's solubility.
• D. It adds a methyl group, altering the protein's charge.

Answer: (C)