This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'The anticoagulant of choice for anticoagulation testing is \nSelect and explain. \nA. Heparin, B. EDTA, C. Sodium oxalate, D. 3.2% trisodium citrate', 'role': 'user'}, {'content': 'Answer: D \nExplanation: MOA - Removes calcium Preferred uses - platelets studies, coagulation studies, ESR Advantages - preserves labile coagulation factors', 'role': 'assistant'}]