Since WrestleMania XXXI, John Cenas United States Championship open challenge has been one of the more entertaining parts of Raw, with an unannounced opponent coming down to have a competitive match with the companys biggest star. Its allowed people like Zack Ryder, Stardust, Sami Zayn, Neville and Xavier Woods to have a televised match where they go toe-to-toe with WWEs cornerstone, often producing good-to-outstanding matches. Part of the fun has been the mystery of who will answer the call. The one problem with this has been that most of the time, Cena has been engaged in a side feud that gets resolved on PPV, so while he defends against random wrestlers on Raw, he has a known opponent one Sunday of the month.That changes at HIAC, when Cena will issue an open challenge for the U.S. title. Speculation has run rampant about whether Dolph Ziggler will answer the call and possibly turn heel in the process. He now is in a six-man tag match during the pre-show, but that doesnt preclude him from competing again. Another rumor is that now that the Wyatt Family/Dean Ambrose and Randy Orton match has been scuttled, Braun Strowman will take up the challenge. There are multiple possibilities here, and WWE could actually go an interesting route and produce a fun moment for the fans. But thats not the only question here