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': 'The clearance of drug means: \nSelect and explain. \nA. Volume of plasma which is cleared of drug in unit of time, B. Amount of drug excreted in urine, C. Amount of drug metabolized in unit of time, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]