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': 'Primary antibody deficiencies are characterized by \nSelect and explain. \nA. Recurrent allergic reactions, B. Recurrent bacterial infections, C. Implicit allergic reactions, D. Implicit bacterial infections', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]