The nurse is caring for a client experiencing respiratory alkalosis. Which of these conditions is a causative agent?

Rationale: A. Pneumonia typically causes respiratory acidosis due to impaired gas exchange and CO₂ retention. B. Brain injuries can affect respiratory patterns, but they are not the most common or direct cause of respiratory alkalosis. C. Anxiety often leads to hyperventilation, which causes excessive loss of CO₂, resulting in respiratory alkalosis. D. Emphysema is associated with CO₂ retention, leading to respiratory acidosis, not alkalosis.