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
Which of the following has immune function in the oral mucous membrane 
Select and explain. 
A. Melanocyte, B. Merkel cell., C. Langerhan cell., D. Keratinocyte
C: Langerhan cell.
Answer: C: Langerhan cell. 
Explanation: None