This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'A pin retained amalgam: \nSelect and explain. \nA. Does not reinforce the tooth, B. Weakens the tooth, C. Reinforces the amalgam structure, D. Improves retention of restoration', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]