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': "'Bioavailability' is defined as: \nSelect and explain. \nA. The volume of plasma completely cleared of a specific compound per unit time and measured as a test of kidney function, B. The percentage of drug that is detected in the systemic circulation after its administration, C. Both, D. None", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]