question: Q:A 36-year-old man presents to his physician with an acute burning retrosternal sensation with radiation to his jaw. This sensation began 20 minutes ago when the patient was exercising at the gym. It does not change with position or with a cough. The patient’s vital signs include: blood pressure is 140/90 mm Hg, heart rate is 84/min, respiratory rate is 14/min, and temperature is 36.6℃ (97.9℉). Physical examination is only remarkable for paleness and perspiration. The patient is given sublingual nitroglycerin, the blood is drawn for an express troponin test, and an ECG is going to be performed. At the moment of performing ECG, the patient’s symptoms are gone. ECG shows increased R amplitude in I, II V3-V6, and ST depression measuring for 0.5 mm in the same leads. The express test for troponin is negative. Which of the following tests would be reasonable to perform next to confirm a diagnosis in this patient?? 
  {'A': 'Blood test for CPK-MB', 'B': 'Echocardiography', 'C': 'Chest radiography', 'D': 'CT angiography', 'E': 'Exercise stress testing'},