【正确答案】 D

【答案解析】A nonrebreathing mask provides the highest possible oxygen concentration--up to 95%. A nasal cannula doesn't deliver concentrations above 40%. A Venturi mask delivers precise concentrations of 24% to 44%, regardless of the client's respiratory pattern, because the same amount of room air always enters the mask opening. A partial rebreathing mask delivers oxygen concentrations up to 90%.