A nurse is preparing to administer 30 units of NPH and 10 units of regular insulin to a client. Which of the following actions should the nurse take?

A. NPH insulin is cloudy due to the presence of protamine. It should be rolled gently between the hands to evenly distribute the particles before drawing it up. B. Insulin can be stored at room temperature for up to 28 days after opening; it does not need to be refrigerated during daily use. C. Air should be injected into the NPH vial first, not the regular insulin vial, to prevent contaminating the regular (clear) insulin with cloudy insulin. D. You should draw up regular (clear) insulin first, then NPH (cloudy), to avoid contamination—not aspirate NPH first.