Week 16. CHAMPIONSHIP!!! Who should I start? Jamaal Charles or Cedric Benson?

My primary back is Chris Johnson. I know if both RB's were given the carries, Benson would probably get more yards and total fantasy points. But Cincy hasn't been running him much. He is only getting half of the carries he is used to. I'm confused! Cincy has a very good rush defense. KC doesn't... WHAT TO DO?!