text: What type of tree is traditionally used for the Rockefeller Centre Christmas Tree?
  A Norway spruce
  B Blue spruce
  C Douglas fir
  The tradition began in 1931, when a group of workers constructing the centre plaza put up their very first tree. Nowadays, this towering wonder stretches up to 27 metres high and is almost always a handsome Norway spruce. To be a contender, this tree must be no less than 22 metres tall and have a trunk with a diameter of 13 metres.
  The correct answer is Norway spruce.