This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunodeficiency, Subject name: Microbiology
[{'content': 'Hypogammaglobinemia causes? \nSelect and explain. \nA. Chronic recurrent sinusitis, B. Epistaxis, C. Contractures, D. Eczema', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Chronic recurrent sinusitisRef.: Harrison 18thedch-316', 'role': 'assistant'}]