<prompt> In TCA cycle, NADH is produced at all sites exceptIsocitrate dehydrogenaseSuccinate dehydrogenaseMalate dehydrogenasePyruvate dehydrogenase  <response>: 6th Step: Formation of Fumarate Succinate is dehydrogenated to fumarate, an unsaturated dicarboxylic acid, by succinate dehydrogenase step 6, Fig.18.2. The hydrogen atoms are accepted by FAD. The FADH2 then enters into ETC to generate ATPs.Ref: DM Vasudevan, 7th edition, page no: 248 