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 most common form of gingival disease is: 
Select and explain. 
A. Gingivitis, B. Periodontitis, C. Gingival recession, D. None of the above
A: Gingivitis
Answer: A: Gingivitis 
Explanation: None