You arrive at the scene shortly after a 55-year-old man collapsed. Two bystanders are performing CPR. The man's wife states that he had cardiac by-pass surgery approximately 6 months earlier. There are no signs of trauma. Cardiac arrest in the adult population is most often the result of

A. an acute stroke
B. respiratory failure
C. cardiac arrhythmias
D. myocardial infarction

Answer: C. cardiac arrhythmias