Please answer the following question: Generate a question about the following movie plot: On New Year's Day, 1976, Apollo Creed has successfully defended his heavyweight title in a split decision, he and Rocky are taken to the same hospital. Apollo challenges Rocky to a rematch, but Rocky declines and officially retires from boxing. His girlfriend Adrian supports his choice, and so do his doctors, who reveal he will require surgery for a detached retina, which could lead to permanent blindness. In a private moment, Rocky goes to see a recuperating Apollo, and wants a truthful response if Apollo gave his all in the fight, to which Creed agrees. After Rocky is released from the hospital, he enjoys the benefits of his life's changes: Rocky's new fame attracts an agent who sees Rocky as a potential endorsement and sponsorship goldmine, and his sudden wealth encourages him to propose to Adrian. She happily accepts, and they marry in a small ceremony. Soon after, Rocky and Adrian happily learn that Adrian is pregnant. Meanwhile, fueled by hate mail, Apollo becomes obsessed with the idea that a rematch is the only way to prove that Rocky's performance was simply a fluke. Determined to rectify his boxing career's only blemish, Apollo ignores all pleas by his friends and family to forget the fight and move on to other potential opponents, and instead demands his team do whatever necessary to goad Rocky out of his hiatus and have a rematch with him. Rocky at first seems unaffected by Apollo's smear campaign, but his inexperience with money causes him to run into financial problems. After largely unsuccessful attempts to find employment, Rocky visits Mickey Goldmill, his trainer and manager, at his gym to talk about the possibility of returning to boxing. At first, Mickey declines, concerned about Rocky's health, but he soon accepts after Apollo publicly insults Rocky. Adrian confronts Rocky about the danger of returning to boxing and reminds him of the risk to his eyesight. Rocky argues he knows nothing else, so this is the only way he can provide. Adrian, furious at Rocky for breaking his promise, refuses...
Answer:
Who is challenging Apollo?