Question: When did the conference the members of the Fresno State–San Diego State rivalry are both part of begin operations?
Sentence (from "Fresno State–San Diego State football rivalry"): The Fresno State–San Diego State football rivalry is an American college football rivalry between the Fresno State Bulldogs football team of California State University, Fresno and San Diego State Aztecs football team of San Diego State University.
Relevant evidence: Yes