The right answer is B.
The Krebs cycle is based on modifying a citrate molecule through enzymes and cofactors. It comprises eight enzymatic reactions that can be decomposed into simple reactions. The cycle thus generates eight different molecules including a new citrate at the end of the cycle. In order, it produces initially citrate, isocitrate, alphaketoglutarate, succinyl CoA, succinate, fumarate, malate, oxaloacetate and regenerated citrate upon arrival. The citrate is reformed, so it is a cycle. A complete turn of the Krebs cycle provides the cell 11 ATP + 1 GTP, a total of 12 ATP.