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: Unknown
All of the following paranasal sinuses are present at birth EXCEPT: 
Select and explain. 
A. Maxillary sinus, B. Ethmoid sinus, C. Sphenoid sinus, D. None
C: Sphenoid sinus
Answer: C: Sphenoid sinus 
Explanation: Ans. (c) Sphenoid sinusRef: Dhingra 5th Ed. / 203Development and Growth of paranasal sinusesSinusesStatus at the birthGrowthFirst radiologic evidenceMaxillaryPresent at birthRapid growth from birth to 3 years and from 7-12 years. Adult size-15yrs4-5 months after birthEthmoidPresent at birthReach Adult size by 12 years1 yearsFrontalNot presentInvades frontal bone at the age of 4 years. Size increases until teens6 yearsSphenoidNot presentReaches sella turcica by the age of 7 years.Reaches full size between 15 years to adult age4 years