Which Statement About the P/O Ratio Is True

Which statement about the P/O ratio is true?

A) It shows that cellular respiration is an inefficient process.
B) It depends on the number of electron acceptor sites on ATP synthase.
C) It represents the amount of ATP produced by oxidative phosphorylation.
D) It has been understood for centuries based on theoretical calculations.
E) It represents the amount of ATP made per glucose molecule.