Which of the following is known as the "Big Three" major US TV networks?

The "Big Three" major US TV networks refer to the three major broadcast television networks that have historically dominated American television viewership. This grouping consists of ABC, NBC, and CBS.

ABC, or the American Broadcasting Company, has been a prominent player in the television industry since its founding in the late 1940s. NBC, the National Broadcasting Company, was one of the first major broadcast networks and has remained a significant presence in television programming. CBS, or Columbia Broadcasting System, has consistently provided a variety of programming and has been a leader in aspects like news, sports, and entertainment.

These networks have significantly shaped American culture and media consumption patterns since their inception. In contrast, the other options involve networks that do not belong to this historically significant grouping. For instance, FOX is indeed a major network but not part of the original "Big Three." Similarly, PBS is a public broadcasting network, focusing on educational content, and ESPN is primarily a sports network. Recognizing the significance of ABC, NBC, and CBS as the traditional leaders helps to understand the landscape of American television and its evolution over the years.