The correct option is D Carbon monoxide
The electron transport chain (ETC) occurs in the inner mitochondrial membrane that has four complexes that accept and carry electrons released from NADH+H+ and FADH2. As the electrons move through different complexes, they release energy. This energy is utilized to pump protons from the matrix to the intermembrane space due to which a proton gradient is generated. Later the protons move through complex V (ATP synthase) into the matrix and there is synthesis of ATP.
Carbon monoxide is an inhibitor of complex IV of the ETC. Complex IV is cytochrome c oxidase. It has cytochromes a and a3 , and two copper centres. This complex transports the electrons to the final electron acceptor i.e oxygen. Cytochrome a3 is disrupted by the inhibitor, carbon monoxide.
Rotenone and amobarbital are inhibitors of complex I.
Antimycin A is an inhibitor of complex III of ETC.