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': 'Threaded pins are used in large dental amalgam restorations to provide: \nSelect and explain. \nA. Retention form, B. Resistance form, C. Occlusal stops for opposing teeth, D. Much needed reinforcement of the amalgam', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]