A client is receiving intravenous (IV) vancomycin and the nurse plans to draw blood for a peak and trough to determine the serum level of the medication. Which of the following collection times provide the best determination of these levels? Which collection times provide the best determination of these levels?

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