What is the final acceptor of electrons in the electron transport chain?
a. carbon dioxide
c. oxygen
b. water
d. pyruvic acid

The final acceptor of electrons in the electron transport chain is "C" , that is oxygen.

The electron transport  chain is composed of a series of electron carriers that operate together to transfer electrons from donors, like NADH and FADH2, to acceptors such as O2.

The electrons flow from carriers with more negative reduction potentials to those with more positive potentials and eventually combine with O2 and H+ to form water. 

The difference in reduction potentials between oxygen and NADH is large, about 1.14 volts and makes possible the release of a great deal of energy.

it would be c. xylem.