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': 'An overhanging proximo-occlusal amalgam restoration leads to: \nSelect and explain. \nA. Decreased retention, B. Increased retention, C. Increased plaque accumulations, D. Fracture of the restoration', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]