A 34-Year-Old Man Is Brought to the Emergency Department with Central

A 34-year-old man is brought to the emergency department with central chest pain and nausea that started two hours ago.  He looks anxious and admits to using cocaine before his chest pain started.  He says that he uses cocaine once or twice per month, but has never had similar symptoms.  He denies any past medical history and exercises regularly at a gym.  He smokes cigarettes and drinks beer on the weekends.  He has no family history of coronary artery disease or sudden death.
On physical examination, he is mildly diaphoretic.  His blood pressure is 165/85 mm Hg and pulse is 105/min.  His oxygen saturation is 98% on room air.  Lungs are clear to auscultation.  There are no murmurs.  Peripheral pulses are brisk and symmetric.
ECG shows sinus tachycardia and a 2 mm ST segment elevation in leads II, III, and avF; a 1 mm ST segment depression is seen in lead I.  Telemetry monitoring shows occasional premature ventricular beats.  Portable chest X-ray is unremarkable.
He is immediately treated with sublingual nitroglycerin, aspirin, and benzodiazepines.  Shortly thereafter, he reports improvement of his symptoms and now rates his chest pain as 3/10, down from the initial 8/10.
Which of the following is the best next step in managing this patient?

A) Cardiac catheterization followed by observation in the coronary care unit
B) Clopidogrel, heparin drip, morphine, and observation in the coronary care unit
C) Esmolol drip, morphine, and observation in the coronary care unit
D) Nitroglycerin as needed, diltiazem, and observation on a telemetry floor
E) Nitroglycerine drip, morphine, and observation in the coronary care unit