A client arrives to the emergency department with chest pain after taking sildenafil. Based on the client's history, which medication should the nurse withhold?

A. Nitroglycerin should be withheld because it can cause severe hypotension when administered to a client who has recently taken sildenafil, which also causes vasodilation. B. Aspirin is generally safe to administer and can help with chest pain, especially if a myocardial infarction is suspected. C. Heparin is an anticoagulant used for treating various conditions and is not contraindicated in this scenario. D. Morphine can be administered to manage severe chest pain, as it is not contraindicated in this situation.