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: Pathology
[{'content': "Deficiency of the 'intrinsic factor of Castle' causes - \nSelect and explain. \nA. Megaloblastic anemia, B. Pernicious anemia, C. Cooley's anemia, D. Aplastic anemia", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]