Final answer:
When a client diagnosed with schizophrenia refuses medication, the nurse should allow the client to decline the medication and document the refusal.
Step-by-step explanation:
When a client diagnosed with schizophrenia refuses medication, it is ethically appropriate for the nurse to allow the client to decline the medication and document the refusal (option A). This is because individuals have the right to make decisions about their own healthcare, including the choice to refuse treatment. However, it is important for the nurse to continue engaging with the client to understand their concerns and explore alternative options if necessary.