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: Dental
When are the crowns of the primary maxillary second molars completed? 
Select and explain. 
A. 11 months., B. 10 months., C. 9 months., D. 8 months.
A: 11 months.
Answer: A: 11 months. 
Explanation: None