This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of Middle Ear (Otitis Media), Subject name: ENT
Which of the following is not a derivative of the middle ear cleft- 
Select and explain. 
A. Semicircular canal, B. Mastoid aircell, C. Tympanic cavity, D. Eustachian tube
A: Semicircular canal
Answer: A: Semicircular canal 
Explanation: Ans. is 'a' i.e., Semicircular canal o The middle - ear cleft in the temporal bone includesEustachian tubeThe middle ear (tympanic cavity)Aditus wrhich leads posteriorly to the mastoid antrum and air cells.