The correct option is D Enzymes of Krebs cycle and protein synthesis
Mitochondrial matrix is a ground substance enclosed by the inner membrane. The matrix is important in the production of ATP with the aid of the ATP-producing enzyme i.e., the enzymes of Krebs cycle. The matrix contains a highly concentrated mixture of hundreds of enzymes, special mitochondrial ribosomes, tRNA, and several copies of the mitochondrial DNA genome and thus, involved in protein synthesis also.