When a client needs oxygen therapy, what is the highest flow rate that oxygen can be delivered via nasal cannula?

The correct answer is 6 liters/minute. When a client requires oxygen therapy, the maximum flow rate that oxygen can be delivered via nasal cannula is 6 liters/minute. Nasal cannula can effectively deliver oxygen up to 6 liters/minute. Flow rates exceeding 6 liters/minute may lead to drying of the nasal passages and discomfort for the client. Higher flow rates, like 8 liters/minute, should be administered using a mask to ensure sufficient oxygenation. Options A, B, and D are incorrect as they indicate flow rates that surpass the recommended maximum for nasal cannula delivery.