This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Regarding severe combined immunodeficiency disease ,which of the following statement is true \nSelect and explain. \nA. Adenosine deaminase deficiency, B. Decreased circulating lymphocytes, C. NADPH oxidase deficiency, D. C1 esterase deficiency', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref Robbins 8/e p234;9/e p239 SCID represent a constellation of genetically distinct syndrome, all having in common defect in both humoral and cell mediated immune response', 'role': 'assistant'}]