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: Anatomy
[{'content': 'Which of the following attains adult size before bih: \nSelect and explain. \nA. Ear ossicles, B. Maxilla, C. Mastoid, D. Mastoid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Ear ossiclesAuditory (ear) ossicles attain full adult size at (or before) bihQ. Although mastoid antrum (air sinus) is well developed (& of adult size) at bih, but mastoid process & air cells develop later.', 'role': 'assistant'}]