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: Microbiology
[{'content': 'Example of an immune complex hypersensitivity reaction is: \nSelect and explain. \nA. Atopic allergy, B. Serum sickness, C. Transfusion reaction, D. Contact dermatitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]