Final answer:
The LP/VN needs to intervene immediately when the NA prepares a client for an enema without properly identifying the client.
Step-by-step explanation:
The action by the nursing assistant (NA) that requires immediate intervention from the licensed practical/vocational nurse (LP/VN) is option b: preparing a client for an enema without first properly identifying the client.
This is a violation of patient safety protocols as proper identification of the client is essential before proceeding with any procedure or intervention.
Identifying the client helps prevent errors, such as administering treatments to the wrong person.