challenge: When did Elmer Theodore 'Ted' Klassen serve as the United States Postmaster General?
  
  A. January 1, 1978 – February 16, 1981
  B. January 1, 1972 – February 16, 1975
  C. January 1, 1965 – February 16, 1968
  D. January 1, 1985 – February 16, 1988
  Answer: 