Only plant cells do photosynthesis but though animal cells don't, they need something equivalent to it.
Cellular respiration is a process that takes place in both animal and plant cells that turns the nutrients (glucose amongst other things) they obtain into ATP (chemical energy), which is also the purpose of photosynthesis (to produce glucose, which can later be converted to ATP).
Answer:
[tex]\boxed{\bf~C.~Cellular~respiration~only.}[/tex]
Hope it helped,
BioTeacher101
