Which of the following definitions matches the term hypotonic?

A. Intravenous solutions are more concentrated than body fluids. They pull fluid from the interstitial spaces and cells into the veins is incorrect because this defines hypertonic solutions. Hypertonic IV fluids have a higher osmolarity than plasma, causing water to move out of cells into the intravascular compartment. While useful in certain situations like severe hyponatremia or cerebral edema, hypertonic fluids dehydrate cells rather than rehydrate them, which is the opposite effect of hypotonic solutions. B. Intravenous solutions are less concentrated than blood and other body fluids. These solutions are used to treat a fluid and electrolyte imbalance by moving water into the cells is correct because hypotonic solutions have a lower solute concentration than plasma. This lower osmolarity causes fluid to shift from the intravascular space into the intracellular space, hydrating cells. Hypotonic solutions are often used in cases of cellular dehydration, such as in hypernatremia or diabetic ketoacidosis, where water replacement inside cells is needed. Examples include 0.45% sodium chloride (half-normal saline) and 0.33% sodium chloride (one-third normal saline). Nurses must monitor patients carefully when administering hypotonic fluids, as excessive use can lead to cellular swelling or cerebral edema. C. Solution that has the same concentration of solutes as human blood is incorrect because this describes an isotonic solution (e.g., 0.9% sodium chloride or lactated Ringer’s). Isotonic fluids maintain fluid balance between the intracellular and extracellular compartments without causing significant shifts in water. D. Administration of a small volume of intravenous solution, connected to and hung higher than a primary intravenous solution is incorrect because this refers to a secondary IV (piggyback) infusion, which is about the method of delivery, not the osmolarity or tonicity of the solution.