Final answer:
The two overriding principles of a health-care proxy or medical power of attorney are Substituted judgment and best interest, reflecting the principles of autonomy and beneficence respectively. Option C is correct.
Step-by-step explanation:
The two overriding principles of a health-care proxy or medical power of attorney are C. Substituted judgment and best interest. These principles ensure that the person designated as the proxy makes medical decisions that the incapacitated individual would have made for themselves, known as substituted judgment, and that choices are made with the intent of serving the patient's best interest. Substituted judgment reflects the principle of autonomy, where an individual has the right to make their own healthcare decisions.
However, when an individual is unable to express their wishes due to incapacity, the appointed health-care proxy is expected to make decisions that align with what the patient would have chosen, based on previous discussions, beliefs, and values, hence executing the individuals’ autonomy vicariously. The principle of best interest dictates that these decisions should also aim at the welfare and well-being of the patient, aligning with the principle of beneficence, which compels acting in ways that benefit the individual.