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 depth of clinical gingival sulcus is the distance between the gingival margin to the 
Select and explain. 
A. Cementoenamel Junction, B. Alveolar crest, C. Apical extension of junctional epithelium, D. Apical penetration of the probe
D: Apical penetration of the probe
Answer: D: Apical penetration of the probe 
Explanation: None