The Same Four Reactions That Are Central to The $\beta$ Oxidation Pathway Are Also Present in the Fatty Acid Synthesis

The same four reactions that are central to the $\beta$ oxidation pathway are also present in the fatty acid synthesis pathway, except they are reversed. What is a key difference between the four reactions in these two pathways?

A) One set of reactions synthesizes an ATP, whereas the other set uses an ATP.
B) One set occurs in the muscle, whereas the second pathway occurs in the liver.
C) One pathway adds three carbon atoms at a time, whereas the other removes two carbons.
D) Four enzymes are used in one, whereas one enzyme is used in the other.