The World Series baseball championship has been played since 1903. There are 30 professional teams in the US and Canada. They are divided into two leagues: the American League and National League. The champions from each league play each other in the World Series. The team that wins the most games out of seven wins the World Series. The New York Yankees have won the Series 26 times. This is more than any other team.
No organization has named the World Series as a "world championship" event. However, sports fans still call it the "world championship of baseball."

What is this passage mainly about?
A.
international championship winning teams
B.
the world champion New York Yankees
C.
how to win a baseball championship game
D.
the World Series baseball championship