challenge: What type of train formations were used for Moonlight Nagara services from December 2013?
  
  A. 185 series electric multiple unit (EMU) 5-car formations
  B. 185 series electric multiple unit (EMU) 10-car formations
  C. 185 series diesel multiple unit (DMU) 8-car formations
  D. 185 series diesel multiple unit (DMU) 12-car formations
  Answer: 