Final answer:
A nurse who makes a medication error that harms a patient could be sued for malpractice, which is a type of professional negligence that leads to harm.
Step-by-step explanation:
A nurse's inadvertent medication error that results in a severe allergic reaction and prolongs a client's hospitalization could lead to a lawsuit for malpractice. Malpractice is a type of negligence that occurs when a healthcare professional fails to perform their duties competently, leading to harm of a patient. This could involve errors in diagnosis, treatment, aftercare or health management. Other options like assault, battery, and abuse do not accurately describe this situation. Assault refers to the threat of harm, battery is the unauthorized making of physical contact, and abuse is the harmful or offensive treatment over a period. In this case, since it was a medication error that caused harm due to professional negligence, malpractice is the correct answer.