A nurse is teaching a newly hired nurse about documentation in the medical record. Which of the following abbreviations should the newly hired nurse identify as a metric unit of weight?

A. mcg: "mcg" stands for microgram, which is a metric unit of weight. It is commonly used in medication dosages to ensure precision in small amounts. B. OZ: "OZ" stands for ounce, which is part of the household/apothecary system, not the metric system. It is sometimes used for fluid or weight but is non-metric. C. lb: "lb" stands for pound, a unit of weight in the avoirdupois system, not the metric system. It is often used in clinical practice but must be converted for precise dosing. D. ML: "mL" stands for milliliter, which is a metric unit, but it measures volume, not weight. It is used for liquids, not solid weight.