A nurse is caring for a client who has a peanut allergy. The client states, "I feel like my throat is closing." Which of the following actions should the nurse take?

A. Give epinephrine intramuscularly: The client is exhibiting signs of anaphylaxis, including throat tightness, which indicates potential airway compromise. Immediate intramuscular epinephrine is the first-line treatment to reverse bronchoconstriction, vasodilation, and hypotension. B. Deliver 2 L of oxygen via partial nonrebreather mask: Oxygen may support oxygenation but does not treat the underlying life-threatening hypersensitivity reaction. Administering epinephrine takes priority over supplemental oxygen in anaphylaxis. C. Notify the radiology department: Notifying other departments is not relevant in this emergency situation. Immediate intervention to manage the allergic reaction takes precedence over routine communication. D. Administer diazepam PO: Diazepam is an anxiolytic and has no role in treating anaphylaxis or airway obstruction. It will not address the life-threatening immune response caused by the peanut allergen.