Final answer:
The nurse should dispose of the medication and document the refusal. Ethical considerations should be taken into account when dealing with a client's refusal of medication.
Step-by-step explanation:
The nurse should take action A, which is to dispose of the medication and document the refusal. It is important for the nurse to respect the client's decision and not force them to take the medication. Asking the client about the reason for refusing and documenting the response (option C) is also a good practice to understand the client's concerns and provide appropriate care. Option B, encouraging the client to take the medication as prescribed, goes against the client's autonomy and should not be done. Option D, administering the medication despite the refusal, is not ethical or legal.