The correct option is A ATP synthase
ATP synthase is an enzyme that synthesises ATP from ADP. Complex V (ATP synthase) of ETC is involved with the synthesis of ATP. Complex V has two components, F0 and F1. F0 forms the channel for the passage of protons and F1 has a site for the synthesis of ATP from ADP and inorganic phosphate.
Hexokinase is an enzyme that helps in converting glucose to glucose-6-phosphate during glycolysis.
Isomerase is an enzyme that helps in converting glucose-6-phosphate to fructose-6-phosphate during glycolysis.
Pyruvate kinase is an enzyme that helps in converting phosphoenolpyruvate to pyruvic acid during glycolysis.