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 predominant cell type in gingival crevicular fluid is the : 
Select and explain. 
A. Mast cell, B. Plasma cell, C. Macrophage, D. Polymorphonuclear leukocyte
D: Polymorphonuclear leukocyte
Answer: D: Polymorphonuclear leukocyte 
Explanation: None