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': 'Oral anticoagulants are monitored by: \nSelect and explain. \nA. Bleeding time (BT), B. Coagulation time (CT), C. Prothrombin time (PT), D. Partial thromboplastin time (PTT)', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]