Task: Question Generation
Input (English): Passage: News of Knut and his life at the zoo was still being reported internationally in late 2007. Knut's restricted diet, intended to curtail the natural weight gain necessary to survive harsh winters, made headlines outside of Germany.  His daily meals were reduced in number from four to three, and treats, such as croissants, which were favored by the young polar bear, were restricted.  After he hurt his foot while slipping on a wet rock in his enclosure a month later in September, there was an outpouring of concern and support from fans worldwide.In November 2007 and weighing over 90 kg (198 lb), Knut was deemed too dangerous for close handling and his interaction with human handlers was further diminished. The celebration of the cub's first birthday, which was attended by hundreds of children, was broadcast live on German television. The national mint also issued 25,000 special commemorative silver coins to mark his birthday.  Knut's role at the Berlin Zoo was to have included his becoming an "attractive stud" for other zoos in order to help preserve his species.  When Flocke was born at the Nuremberg Zoo in December 2007 under similar circumstances, Bild dubbed her  Mrs. Knut, suggesting that the two German-born polar bears might become mates when they matured.
Output (English): Whose birthday was marked by a special coin?