A 6-year-old boy has been brought to the emergency department by ambulance after his mother ...

A 6-year-old boy has been brought to the emergency department by ambulance after his mother discovered that his heart rate was so fast I couldn't even count it.
 
  The child was determined to be in atrial flutter, and his mother is seeking an explanation from the health care team. Which of the following points should underlie an explanation to the mother?
  A)
  The child is experiencing a reentry rhythm in his right atrium.
  B)
  The resolution of the problem is dependent on spontaneous recovery and is resistant to pacing interventions.
  C)
  The child is likely to have a normal ECG apart from the rapid heart rate.
  D)
  The boy's atria are experiencing abnormal sympathetic stimulation.