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
After the tooth emerges to the occlusal plane the clinical
crown height increases by: 
Select and explain. 
A. Passive eruption, B. Active eruption, C. Post-emergence growth spurt, D. Juvenile occlusal equilibrium
A: Passive eruption
Answer: A: Passive eruption 
Explanation: None