For San Francisco 49ers coach Kyle Shanahan, the biggest risk wasn’t trading three first-round picks for the No. 3 selection where he could take a shot on the franchise quarterback of the future. The chance he didn’t want to take going forward anymore was going into a season without an elite quarterback who he believes can consistently carry a team to a Super Bowl. “It’s a risk every single year you go into an NFL season without one of those top five guys,” Shanahan said Monday in his first public comments since last week’s big trade for the No. 3 pick.