You are answering a USMLE-style medical question. Question: A previously healthy 28-year-old man comes to the emergency department because of dizziness and palpitations for 2 days. Prior to the onset of the symptoms, he attended a bachelor party where he lost several drinking games. An ECG is shown. Which of the following is the most likely diagnosis? Options: A) Paroxysmal atrial fibrillation B) Brugada syndrome C) Ventricular tachycardia D) Sick sinus syndrome Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.