A. The statement that no drug remains is incorrect. A drug with a half-life of 8 hours will not be completely eliminated in 24 hours, as it follows a predictable pattern of reduction. B. A reduction to 50 mg would require additional half-life intervals beyond 24 hours. The drug concentration decreases by half every 8 hours, meaning it would take more than 24 hours to reach this level. C. The correct calculation follows the half-life principle: - At 8 hours: 800 mg → 400 mg - At 16 hours: 400 mg → 200 mg - At 24 hours: 200 mg → 100 mg Therefore, 100 mg of the drug remains after 24 hours. D. While 200 mg is a step in the process, it represents the amount remaining after only 16 hours, not the full 24-hour period.