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
[{'content': "The function of Langerhan's cells is \nSelect and explain. \nA. Melanin synthesis, B. Protein synthesis, C. Antigen presentation to neutrophils, D. Antigen presentation to lymphocytes", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]