Kamila Valieva, the Russian figure skater at the Beijing Olympics, was granted the opportunity to participate in the Olympics despite failing a drug test by which regulatory body of sport?

Group of answer choices

International Skating Federation $($ISF$)$

World Players Association $($WPA$)$

World Anti$-$Doping Agency $($WADA$)$

Court of Arbitration of Sport $($CAS$)$