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
The position of mucogingival line 
Select and explain. 
A. Shifts apically with age, B. Shifts coronally with age, C. Constant throughout the life, D. None of the above
C: Constant throughout the life
Answer: C: Constant throughout the life 
Explanation: None