A client, whose cancer is very advanced, has decided not to have surgery or chemotherapy. The nurse believes that, as a rule, everything possible should be done to preserve life. However, once the client has decided, the nurse supports the decision. Which ethical principle provides the best basis for the nurse's actions?

The correct answer is D: Respect for autonomy. Autonomy is the ethical principle that recognizes an individual's right to make their own decisions about their own care. In this scenario, the client has made an informed decision to forgo surgery and chemotherapy, exercising their autonomy. The nurse's role is to respect and support the client's autonomy by honoring their decision. This includes providing information, ensuring the decision is voluntary, and supporting the client's right to make choices about their own healthcare. Choices A, B, and C (Justice, Nonmaleficence, and Beneficence) are not as relevant in this context because the main ethical principle at play here is respecting the client's autonomy in decision-making.