What do anaerobic organisms have in common with photosynthetic organisms?

a.) they both appeared on earth at about the same time.
b.) they both can only exist as single-celled organisms.
c.) they both need an energy source in order to survive.
d.) they both produce carbon dioxide as a waste product.

Ans is option C. They both need an energy source in order to survive.

Energy is an absolute necessity to survive on this earth. All living organisms need energy be it anaerobic or photosynthetic.  Photosynthetic organisms can make their own food in the presence of sunlight by photosynthesis and harness energy from it. Anaerobic organisms can also make their own food in the absence of sunlight with the help of inorganic molecules like hydrogen sulfide (H2S), ammonia (NH3), sulphur (S) etc.

Its just that anaerobic organism's way of harnessing energy is different from those of aerobes/photosynthetic organisms but they need energy source for sure.

substitution is the answer in this case