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': 'Force required for headgear to restrain maxillary growth is: \nSelect and explain. \nA. 50-100 gm per side, B. 150-200 gm per side, C. 250-500 gm per side, D. 750-1000gm per side', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]