NEW YORK—According to TV viewer Maurice Degroot, every phase of rock band The Who's career was traced by a single CBS commercial break Tuesday. "The retrospective opened with Hummer's 'Happy Jack,' one of the songs from The Who's '60s mod period,"Degroot said. "Then a Saab commercial played 'I'm Free' from their ambitious rock-opera phase, followed by a promo for CSI featuring 'Who Are You,' one of their last great hits." In light of the popular commercials, the surviving Who members are planning a reunion tour to perform 30-second snippets from all their famous songs.