Which of the following schools is a part of the Big Ten Conference?

The University of Iowa is indeed a member of the Big Ten Conference, which is a collegiate athletic conference known for its strong academic institutions and competitive athletic programs, particularly in sports like basketball and football. The Big Ten includes schools that are primarily located in the Midwestern United States, and the University of Iowa has a rich history in intercollegiate athletics, making it a significant member of this conference.

Other options represent schools that belong to different conferences. For instance, the University of Arizona is part of the Pac-12 Conference, which includes schools primarily from the western part of the country. Northwestern University is also in the Big Ten Conference, which means that it is relevant to the question but not the chosen answer. The University of Oklahoma is a member of the Big 12 Conference, which is separate from the Big Ten and includes schools primarily from the central part of the United States. This context about the affiliations of the other schools helps clarify why the University of Iowa stands out as the correct choice in the context of the Big Ten Conference.