How did the German Kaiser Wilhelm Il get to meet the Indian resistance leader Sitting Bull?

a. Sitting Bull was part of Buffalo Bill's world tour through Europe.
b. Wilhelm II had traveled to a German-owned western ranch in his young years.
c. Wilhelm visited German immigrants in Washington at the time the U.S. army brought the chief into town as prisoner.
d. Sitting Bull was a close friend of German author and Kaiser favorite Karl May,