Choice A reason: Removing the nasal cannula is not appropriate as it would deprive the client of supplemental oxygen. The client's oxygen saturation is below the normal range of 95% to 100%, indicating hypoxemia. Choice B reason: While increasing oxygen might seem appropriate, this should only be done after verifying the accuracy of the pulse oximeter reading and assessing the client’s overall condition. Automatically increasing oxygen without further assessment could delay addressing other underlying issues or lead to over-oxygenation in clients with certain conditions like COPD. Choice C reason: The first step is to ensure the accuracy of the pulse oximeter reading by checking its placement and ruling out factors that can interfere with accurate readings, such as poor circulation, cold extremities, nail polish, or motion artifacts. This ensures that the subsequent intervention is based on reliable data. Choice D reason: Switching to a non-rebreather mask is not necessary as it would deliver a high concentration of oxygen (up to 100%) that may be excessive for the client. A nasal cannula can deliver oxygen from 1 to 6 L/minute, depending on the client's needs.