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: Ophthalmology
[{'content': 'The most common mucocele of the paranasal sinuses involving the orbit arises from: \nSelect and explain. \nA. Frontal sinus, B. Ethmoidal sinus, C. Maxillary sinus, D. Sphenoidal sinus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Frontal sinus', 'role': 'assistant'}]