Cellular work is carried out by the different types of molecules that the cell assembles.
Cellular work requires getting energy by breaking energy-containing bonds in certain molecules (like ATP).
This kind of work doesn't involve only DNA and RNA (not D).
Energy-deficient compounds don't have energy, so they can't power cellular work (not B).
I don't think C is the best answer because cellular work (like breaking/making bonds) can be facilitated by enzymes and other molecules made by the cell itself, not just other organisms that have a symbiotic relationship with the cell (not C).
