After weeks of guest hosts on "Jeopardy" that included celebrities from TV, sports and journalism, the daily syndicated quiz show chose its executive producer, Mike Richards, as the successor to beloved host Alex Trebek. But after fan backlash to a selection process that turned messy in recent weeks, producer Sony split the pie by naming another guest host, actress Mayim Bialik, as emcee for "Jeopardy" prime-time and spinoff series, including a new college championship.