Final answer:
A Registered Nurse (RN) should never delegate tasks involving critical thinking and decision-making, as these are essential responsibilities that require an RN's advanced training and direct supervision.
Step-by-step explanation:
The task the Registered Nurse (RN) should never delegate or assign is option (d) Critical thinking and decision-making. This is because these functions are central to the core responsibilities of an RN and require professional judgement that comes from their higher level of education and training. RNs must provide direct supervision for tasks like assessing patient conditions and responding to their needs during procedures, such as providing dialysis treatments. It's essential for RNs to apply critical thinking when reviewing patient history, monitoring the treatment process, and ensuring accuracy and sterility during procedures.
RNs are also responsible for making sure all aspects of a procedure are completed correctly. For instance, ensuring that needle, sponge, and instrument counts are accurate, specimens are correctly labeled, and any issues with equipment are addressed, is a non-delegable responsibility to maintain patient safety.