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': 'Runt disease is ? \nSelect and explain. \nA. Graft rejection, B. Graft vs host disease, C. Host vs graft disease, D. Type III hypersensitivity', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Graft vs host disease", 'role': 'assistant'}]