Final answer:
Given Mrs. Smith's informed refusal, respecting her autonomy and proceeding with her chosen plan of care align with medical ethics.
Step-by-step explanation:
The subject of this question pertains to medical ethics and the management of a pregnant HIV-positive woman with a low CD4 count and high viral load. Given Mrs. Smith's condition, reducing mother-to-child HIV transmission is crucial. Methods for this include antiretroviral medications during pregnancy and to the infant after birth, cesarean delivery, and avoiding breastfeeding. Despite the recommendations for a Caesarian section and intravenous zidovudine to lower the transmission risk, Mrs. Smith refuses the interventions. In this situation, option A) respecting Mrs. Smith's autonomy and continuing with her chosen plan of care is aligned with the principles of bioethics, assuming she has been fully informed and is capable of making her own medical decisions.