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': 'The pins in an amalgam restorative serve to: \nSelect and explain. \nA. Increase strength, B. Increase retention, C. Increase resistance of fracture, D. All the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]