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: Pathology
Anti coagulant used in coagulation study is - 
Select and explain. 
A. Calcium citrate, B. EDTA, C. Sodium bromide, D. Trisodium citrate
D: Trisodium citrate
Answer: D: Trisodium citrate 
Explanation: Answer- D. Trisodium citrateFor coagulation studies: Trisodium citrate (citric acid).