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 patient diagnosed to have deep vein thrombosis is being treated with heparin. Which of the following test will you order to adjust its dosage : \nSelect and explain. \nA. Platelet count, B. Prothrombin time, C. Bleeding time, D. Activated partial thromboplastin time', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]