challenge: When and where did the Hydrogen Council launch?
  
  A. January 7, 2018, at the World Economic Forum in Zurich
  B. June 1, 2019, at the World Economic Forum in Bern
  C. December 31, 2016, at the World Economic Forum in Geneva
  D. January 7, 2017, at the World Economic Forum in Davos
  Answer: 