challenge: According to critic Scott Yanow, what is the primary reason to acquire the 1973 album 'The Trio'?
  
  A. The production quality of Norman Granz's Pablo label
  B. The playing of Joe Pass and Niels-Henning Ørsted Pedersen
  C. The pianist's investigation of several jazz styles by Oscar Peterson
  D. The album's historical significance in the jazz genre
  Answer: 