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: Surgery
[{'content': 'A 32 year old male patient complains of swelling in left maxillary region with heaviness in the maxillary sinus following tooth extraction of maxillary first molar. Patient gives a history of tooth extraction one week before with transalveolar type of extraction.\n\nThe average mucociliary air flow transport in the maxillary sinus is \nSelect and explain. \nA. 5 to 20mm per min, B. 5 to 20 cm per min, C. 5 to 20 km per min, D. 5 to 20 dm per min', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]