Which RB to flex

HPPR. I am starting Kamara and Barkley. I have Ballage (sitting), Murray who did very well while Kamara was out, and Singletary. Which do I flex

Singletary fairly easy start for me there. Ballage is garbage, and Murray might only get like 5 touches, not a risk I am taking.

Singletary without question

Singletary for me