A nurse is planning to administer a controlled substance to a client who is experiencing pain. Which of the following actions should the nurse plan to take first?

The correct answer is A: Identify the client using two identifiers first. This is crucial to ensure the right medication is given to the right patient, preventing medication errors. By verifying the client's identity using two identifiers (such as name and date of birth), the nurse confirms they are administering the medication to the intended recipient, enhancing patient safety. Removing the medication from the cabinet, comparing inventory, or documenting administration can all follow once the client's identity is verified. Identifying the client is the priority step to ensure safe medication administration.