Which WRs should I start for week 15?

Marshall, Crabtree, Berrian and Wallace. Crabtree will have to have a big game, especially if (when) the niners fall behind. Berrian and the rest of the Vikes are going to continue to play like it is the playoffs, and Brett is wanting to show the world that he doesn't have a problem playing in December. Wallace is the least of the last three evils.