Auto Unlock Not Working

On my MacBook Pro (Retina, 13-inch, Early 2015) auto unlock is not showing up under security and privacy. I am currently running OS Sierra on my mac, WatchOS 3, have 2 factor authentication on, and my watch has a password. When I go to security and privacy under system prefrences, there is no option for me to turn on auto unlock. Any help would be appreciated.