Final answer:
A nurse's use of assertive behavior involves being open and direct when asked by the nurse manager to complete assignments.
Step-by-step explanation:
A nurse's use of assertive behavior is best described as being open and direct when asked by the nurse manager to complete assignments. This means that the nurse confidently expresses their opinions, thoughts, and needs without being aggressive or passive. They communicate their ideas clearly and respectfully, while taking responsibility for their actions.