The nurse is aware that the compensating mechanism, that is most likely to occur in the presence of respiratory acidosis is:

Rationale: A. In respiratory acidosis, CO₂ accumulates in the blood due to hypoventilation, lowering the pH. The kidneys compensate by retaining HCO₃ (bicarbonate), which helps buffer excess hydrogen ions and raise the pH toward normal. B. Hypoventilation causes or worsens respiratory acidosis by increasing CO₂ levels, so it is not a compensatory response. C. Excreting HCO₃ would lower the pH further and worsen the acidosis, so this is incorrect. D. Hyperventilation helps reduce CO₂ levels but is a respiratory response, not a renal compensatory mechanism. Compensation for respiratory acidosis primarily occurs via the kidneys, not the lungs.