Fuel Cells Are Being Developed for Commercial Use That Use

Fuel cells are being developed for commercial use that use hydrogen as a fuel. In these cells, hydrogen combines with oxygen in the air to produce water as the only product. This combination appears to be a perfect source of energy, except hydrogen is highly explosive and challenging to store. The fuel cells produce no waste products because the water essentially is recycled, and the energy is obtained from the sun rather than from fossil fuels. When 1 mol of oxygen gas is ________ in the fuel cell, ________mole(s) of electrons are transferred.

A) reduced, 1
B) reduced, 2
C) oxidized, 2
D) reduced, 4
E) oxidized, 4