A nurse tells a patient that they will return in 30 minutes with their medication. The nurse returns 30 minutes later with the patient's medication. Which ethical principle is she demonstrating?

A. Nonmaleficence: Nonmaleficence means "do no harm," which is not the main principle demonstrated here. B. Justice: Justice refers to fairness in care and treatment distribution, which is not relevant to keeping a promise. C. Beneficence: Beneficence involves actions that promote the well-being of a client, but this scenario specifically demonstrates truthfulness. D. Veracity: Veracity refers to truthfulness and honesty. The nurse demonstrated veracity by keeping their promise and returning with the medication as stated.