The correct option is A Alpha-ketoglutaric acid
TCA cycle is an amphibolic pathway in which some substrates like the alpha-ketoglutarate, oxaloacetate, citrate, acetyl CoA etc. can be used both in catabolic and anabolic pathways. Alpha-ketoglutarate (alpha-ketoglutaric acid) is used in the synthesis of various amino acids like the glutamate.