Final answer:
If angina pain persists 5 minutes after taking a nitroglycerin tablet, seeking emergency care is crucial as it may indicate an imminent heart attack or unstable angina.
Step-by-step explanation:
If a patient with angina pain has no relief from the pain 5 minutes after administering a nitroglycerin tablet, the appropriate course of action would be A. Seek emergency care. Nitroglycerin is typically used to relieve chest pain (angina) in people with certain heart conditions by dilating the coronary arteries to improve blood flow. If the pain persists after the initial dose, it may indicate unstable angina or an imminent heart attack, which requires immediate medical attention. Waiting longer or taking additional tablets without medical advice can be dangerous in this critical situation.