A client is receiving intravenous vancomycin, and the nurse plans to draw blood for a peak and trough to determine the serum level of the drug. Which collection times would provide the best determination of these levels?

C Thirty minutes into the administration of the IV dose and 30 minutes before the next administration of the medication. D Immediately after completion of the IV dose and 30 minutes before the next administration of the medication. B Two hours after completion of the IV dose and two hours before the next administration of the medication. A One hour after completion of the IV dose and one hour before the next administration of the medication.