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: ENT
[{'content': 'Not true about Frontal sinus \nSelect and explain. \nA. Osteomas are common, B. Sinusitis leads to morning headaches, C. Opens into middle meatus, D. Present at Birth', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]