What is the treatment of choice of this condition?

37-year-old previously healthy man is brought to the emergency room for dizziness, chest pain and palpitations. Cardiac chemistry panel is normal. ECG shows a sloping upstroke of the QRS complex.
What is the treatment of choice of this condition?

A-Atropine
B-Digoxin
C-Metoprolol
D-Procainamide
E-Verapamil