Please answer the following question: Given the following passage  "Oklahoma City is the annual host of the Big 12 Baseball Tournament, the World Cup of Softball, and the annual NCAA Women's College World Series. The city has held the 2005 NCAA Men's Basketball First and Second round and hosted the Big 12 Men's and Women's Basketball Tournaments in 2007 and 2009. The major universities in the area – University of Oklahoma, Oklahoma City University, and Oklahoma State University – often schedule major basketball games and other sporting events at Chesapeake Energy Arena and Chickasaw Bricktown Ballpark, although most home games are played at their campus stadiums.",  answer the following question. Note that the answer is present within the text.  Question: What organization usually holds it's sporting events in Oklahoma City?
Answer:
Big 12