This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Microbiology Pa 1 (History, Microscopy, Stains and Structure and Physiology of Bacteria), Subject name: Microbiology
[{'content': 'Which anticoagulant is used when blood is sent for blood culture- \nSelect and explain. \nA. Sodium citrate, B. EDTA, C. Oxalate, D. SPS', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Blood culture media contain 0.03% SPS (Sodium polyenathol sulfonate), a polyanionic anticoagulant which additionally inhibits complement and lysozyme activity. It inactivates inhibitory substances which are present in blood.', 'role': 'assistant'}]