The nurse is assisting in the development of a care plan for a patient with pernicious anemia. Which of the following would be the most common nursing diagnosis with this medical condition?

A. Ineffective airway clearance is not a primary concern in pernicious anemia, as dyspnea is usually mild and related to anemia rather than airway obstruction. B. Pernicious anemia primarily affects red blood cells, not WBCs, so risk for infection is less common. C. Chronic pain related to bone marrow dysfunction is more associated with leukemia or other marrow disorders, not typical in pernicious anemia. D. Activity intolerance related to tissue hypoxia is the most common nursing diagnosis for pernicious anemia because vitamin B12 deficiency leads to decreased red blood cell production, reducing oxygen delivery to tissues and causing fatigue and weakness.