Which conference does Washington State belong to?

Washington State University is a member of the Pac-12 Conference. This conference, known for its competitive athletic programs, primarily spans the western United States and includes several schools that are well-known for their strong basketball teams. The Pac-12 is recognized for its history and success in NCAA basketball, producing numerous successful teams and athletes over the years. Washington State's inclusion in this conference aligns with its geographic location and athletic affiliation, as the Pac-12 has traditionally included schools from the West Coast and is known for a high level of competition in various sports, including basketball.

The other conferences listed, such as Big Ten, ACC, and the American Athletic Conference, do not include Washington State, making them incorrect options in this context.