The correct option is D Substrate level phosphorylation
PEP+ADP→pyruvic acid+ATP
During the conversion of phophoenol pyruvate (PEP) to pyruvic acid, the phosphate group from PEP is transferred to ADP. Therefore it is substrate level phosphorylatron. In oxidative phophorylation, the electrons from high energy carirer travel along an ETC, and finally to an external electron acceptor, that is oxygen. The energy from this process is used to synthesize ATP. Hence known as the oxidative phosphorylation.