Fatty acids usually have an even number of carbons in their structures. they are catabolized by a process called beta-oxidation. the end products of the metabolic pathway are acetyl groups of acetyl coa molecules. these acetyl groups

a) directly enter the electron transport chain
b) directly enter the energy-yielding stages of glycolysis
c) are directly decarboxylated by pyruvate dehydrogenase
d) directly enter the citric acid cycle

D. Directly enter the citric acid cycle

Explanation:

In biochemistry and metabolism, beta-oxidation is the catabolic process by which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport chain. The NADH and FADH2 produced by both beta oxidation and the TCA cycle are used by the mitochondrial electron transport chain to produce ATP. Complete oxidation of one palmitate molecule (fatty acid containing 16 carbons) generates 129 ATP molecules.