Who along with Richard Hoggart and Stuart Hall was one of the founding figures of the school of thought now known as British Cultural Studies?

The correct option is Raymond Williams.

British Cultural Studies emerged in the late 1950s and 1960s, primarily associated with the Centre for Contemporary Cultural Studies (CCCS) at the University of Birmingham. The foundation of this school of thought is widely attributed to three key pioneering figures:
1. Richard Hoggart, who founded the CCCS in 1964 and wrote the influential book The Uses of Literacy (1957).
2. Raymond Williams, whose seminal books Culture and Society (1958) and The Long Revolution (1961) laid the theoretical groundwork for analyzing culture as a "whole way of life" rather than just high art.
3. Stuart Hall, who succeeded Hoggart as the director of the CCCS and significantly expanded the field's focus to include race, gender, media representation, and power dynamics.

Among the other options listed:
- Walter Benjamin was an influential German philosopher and cultural critic associated with the Frankfurt School, not British Cultural Studies.
- Stephen Greenblatt is an American literary historian who pioneered New Historicism.
- Helen Tiffin is a prominent Australian postcolonial theorist.

Therefore, Raymond Williams is the correct founding figure who completes the trio alongside Richard Hoggart and Stuart Hall.