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: Physiology
[{'content': 'The anticoagulant of choice used in the blood bank is: \nSelect and explain. \nA. Calcium oxalate, B. Heparin solution, C. Acid citrate dextrose solution, D. Sodium fluoride', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]