challenge: What type of rolling stock is used on the FL2 route?
  
  A. Only Treno ad alta frequentazione electric multiple units
  B. None of the above
  C. Only MDVE coaches hauled by E.464 class electric locomotives
  D. A mixture of Treno ad alta frequentazione electric multiple units and MDVE coaches hauled by E.464 class electric locomotives
  Answer: 