Why Is the Citric Acid Cycle Considered to Be Part

Multiple Choice

Why is the citric acid cycle considered to be part of aerobic metabolism, even though oxygen is not a substrate in any reaction?

A) because it takes place in the mitochondrion
B) because it contains oxidation reactions
C) because it produces reduced electron carriers, which are reoxidized by transferring their electrons ultimately to oxygen
D) because NADH and FADH₂ produce a lot of ATP when reoxidized
E) because it produces carbon dioxide