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': 'Adenosine deaminase deficiency is seen in the following disease \nSelect and explain. \nA. Common variable immunodeficiency, B. Severe combined immunodeficiency, C. Chronic granulomatous disease, D. Nezelof syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]