The overall equation for cellular respiration is 1 glucose molecule plus diatomic oxygen (6 molecules of O2) and produces energy in form of ATP plus carbon dioxide (6 molecules of CO2), and water (6 molecules of H2O), as stated in the D answer option, 1 glucose + 6 oxygen = 6 carbon dioxide + energy.
This process can be compared with photosynthesis, which it's kinda the counterpart of it since in it, the process begins with 6 CO2 molecules, and 6 H2O molecules and produces the 1 glucose molecule and 6 molecules of O2.
