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: Pharmacology
[{'content': 'A PTT is required for monitoring of ? \nSelect and explain. \nA. Streptokinase, B. Warfarin, C. Heparin, D. Tranexamic acid', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is'c'i.e., Heparin(Ref KDT &/e p. 598, 599; Katzung llnle p. 592)", 'role': 'assistant'}]