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
Which anticoagulant is used when blood is sent for blood culture- 
Select and explain. 
A. Sodium citrate, B. EDTA, C. Oxalate, D. SPS
D: SPS
Answer: D: SPS 
Explanation: 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.