A nurse is assessing a client who has asthma and signs of central cyanosis. Which of the following is a reliable indicator of cyanosis?

A. Oral mucosa: The oral mucosa is a reliable indicator of central cyanosis because it reflects oxygenation of arterial blood. Bluish discoloration in the lips, tongue, or inside the mouth indicates significant hypoxemia. B. Ear lobes: The ear lobes are more commonly used to detect peripheral cyanosis, which may occur with vasoconstriction or reduced blood flow, and is less reliable for assessing overall oxygenation. C. Tip of the nose: The tip of the nose is susceptible to temperature and peripheral perfusion changes, making it an unreliable site for detecting central cyanosis. D. Eye lids: The eyelids are not a reliable site for assessing cyanosis because their color can be affected by lighting, skin tone, and perfusion, and they do not accurately reflect arterial oxygenation.