While the nurse is conducting an admission assessment of a female client with bipolar disorder, the client suddenly begins to take off her clothes and throw them about the room. Which action should the nurse take first?

A: Leaving the client alone could increase the risk of harm to herself or others and does not address the immediate need for safety and boundaries. B: Clearly stating that undressing is unacceptable sets immediate boundaries, which is essential in managing acute behavioral situations, ensuring the client's dignity, and maintaining a professional environment. C: Ignoring the behavior does not provide any guidance or boundaries for the client, which could lead to escalation or reinforce the inappropriate behavior. D: While changing to less anxiety-provoking questions may be helpful, it does not directly address the behavior at hand, which could lead to further inappropriate actions or misunderstandings about acceptable behavior during the assessment.