Question: When did the conference the UNLV Runnin' Rebels are a member of begin operations?
Sentence (from "1989–90 UNLV Runnin' Rebels basketball team"): The 1989–90 UNLV Runnin' Rebels basketball team represented the University of Nevada Las Vegas in NCAA Division I men's competition in the 1989–90 season, and won the NCAA title under head coach Jerry Tarkanian.
Relevant evidence: Yes