C.  

Succinate dehydrogenase uses covalently bound flavin adenine dinucleotide (FAD) as its redox cofactor and does not require thiamine pyrophosphate, whereas α-ketoglutarate dehydrogenase, branched-chain α-keto-acid dehydrogenase, and pyruvate dehydrogenase all depend on thiamine pyrophosphate for decarboxylation of α-ketoacids [Steginsky 1984 PMID 6368556; Sümegi 1983 PMID 6859868; Robinson 1996 PMID 8626739].