A. Incorrect response: See explanation C.
B. Incorrect response: See explanation C.
C. Correct response: In contrast to inhaled NO (iNO), intravenous vasodilators (e.g., sodium nitroprusside and nitroglycerin) are not selective vasodilators. Although intravenous vasodilators lower pulmonary artery pressure, they also lower systemic blood pressure. Moreover, these agents increase blood flow to both ventilated and unventilated alveoli, resulting in increased intrapulmonary shunting and a lower Pao2.
D. Incorrect response: See explanation C.