College football rankings, grades: Michigan deserves an 'A+', Ohio State, Oklahoma earn an 'F' | CBS Sports Headlines College football rankings, grades: Michigan deserves an 'A+', Ohio State, Oklahoma earn an 'F' A look at how the national championship contenders fared in Week 13 and their updated odds ESN FeedsThis … Continue reading College football rankings, grades: Michigan deserves an 'A+', Ohio State, Oklahoma earn an 'F'