Citric acid is formed in the kreb cycle when
malic acid combines with acetyl CoA.
oxaloacetic acid combines with acetyl CoA.
oxalosuccinic acid combines with acetyl CoA.
fumaric acid combines with acetyl CoA.
Condensation of oxaloacetic acid with acetyl group acetyl Co.A and water yields citric acid in the presence of the enzyme citrate synthase.