A client who underwent cardiac stent placement four days ago arrives to the emergency department reporting a sudden onset of chest pressure and shortness of breath. Which action should the nurse take next?

A. While monitoring troponin levels is important for diagnosing myocardial infarction, immediate relief of chest pressure and shortness of breath is a higher priority. B. Placing an indwelling urinary catheter and measuring intake and output is not the immediate priority for managing acute chest pain and potential myocardial ischemia. C. Counting premature ventricular contractions is useful but not the most immediate action in managing acute chest pressure and shortness of breath. D. Recording the pain score and administering sublingual nitroglycerine addresses the acute symptoms of chest pressure and shortness of breath, aiming to relieve myocardial ischemia.