This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Pharmacology, Subject name: Pharmacology
[{'content': 'A patient was given a 160 mg dose of a drug IV, and 80 mg was eliminated during the first 120 minutes. If the drug follows first-order elimination kinetics, how much of the drug will remain 6 hours after its administration? \nSelect and explain. \nA. None, B. 10 mg, C. 20 mg, D. 40 mg', 'role': 'user'}, {'content': 'Answer: C \nExplanation: One half of the drug dose is eliminated in 120 min, so its elimination half-life = 2 hours. With the passage of each half-life, the amount in the body (or in the blood) will decrease to 50% of a former level. Thus, at 6 hours after drug administration, the amount of drug remaining is 160 divided by (2x2x2) or 160/8=20mg.', 'role': 'assistant'}]