This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
[{'content': 'Paranasal sinuses present at bih \nSelect and explain. \nA. Frontal and maxillary, B. Ethmoid and maxillary, C. Frontal and ethmoid, D. Sphenoid and ethmoid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The sinuses are rudimentary or even absent at bih.They enlarge rapidly during the age of 6 to 7 years i.e, at thevtime of eruption of permanent teeth and then after pubey.From bih to adult life, the growth of the sinuses is due to the enlargement of the bones; in old age, it is due to resorption of the surrounding cancellous bone. Ethmoid and maxillary sinuses present at bih Ref BDC volume;3.Sixth edition', 'role': 'assistant'}]