Correct Option: C

Glutamate dehydrogenase (GLDH) is an enzyme, present in most microbes and the mitochondria of eukaryotes, as are some of the other enzymes required for urea synthesis, that converts glutamate to α-ketoglutarate, and vice versa.
The α-ketoglutarate to glutamate reaction does not occur in mammals as glutamate dehydrogenase equilibrium favours the production of ammonia and α-ketoglutarate. NAD+ or NADP⁺ is a cofactor for the glutamate dehydrogenase reaction, producing α-ketoglutarate and ammonium as a byproduct.