A nurse is assisting in the plan of care for a client who has a suspected myocardial infarction. Which of the following medication should the nurse plan to administer first?

A. Morphine is used for pain unrelieved by nitroglycerin, but it does not address clot formation and is not the first-line medication. B. Nitroglycerin relieves chest pain by vasodilation but is given after aspirin (and contraindicated if hypotension or PDE5 inhibitors are present). C. Aspirin: The priority is to administer chewable aspirin immediately because it inhibits platelet aggregation and reduces further clot formation, directly addressing the cause of the infarction. D. Oxygen is given if the client’s oxygen saturation is <90%, but it is not the first intervention unless hypoxemia is present.