Final answer:
The best nursing action when taking a small child's blood pressure is to choose the smaller cuff and apply it correctly to ensure accuracy.
Step-by-step explanation:
When taking a child's blood pressure, it is important to use the correct-sized cuff for accurate measurements. Neither using a larger cuff nor applying a smaller cuff tightly is the best nursing action. The nurse should choose the smaller cuff and apply it correctly to the child's arm. Using the smaller cuff will help ensure accurate readings by providing the right amount of pressure on the artery. If none of the available cuffs fit properly, the best action would be to seek assistance from another healthcare provider who may have access to a cuff that fits the child properly.