The San Francisco 49ers answered their biggest player contract question by signing quarterback Colin Kaepernick to an extension through the 2020 season.Who do you think should be next?Receiver Michael Crabtree and guard Mike Iupati are their other top players whose contracts expire after the 2014 season. They also are dealing with two players who want new deals. Tight end Vernon Davis and guard Alex Boone have both stayed away from the voluntary sessions of the offseason.