challenge: What are the typical configurations of motorized trikes?
  
  A. One wheel in the front, two in the rear, and a sidecar
  B. Three wheels in the front, one in the rear
  C. Two wheels in the rear, two in the front
  D. Two wheels in the rear, one in the front (aka trike) and two in front, one in the rear (aka reverse trike)
  Answer: 