The correct option is D They are catabolic, bacause the free energy decreases as a result of the process.
Metabolism refers to series of reactions wherein product of one reaction becomes reactant for the next one. It includes catabolism (degradative pathways) and anabolism (synthetic pathways). Conversion of fatty acids into acetyl CoA is a catabolic pathway as chemical energy stored in fatty acids is released during the breakdown of this complex molecule into simpler ones i.e. acetyl-CoA. Anabolic pathways use the chemical energy to build complex molecules from simpler one and the free energy of the end product is higher than the reactants. Thus, the correct statement is D.