How Is It Possible for Humans to Use Some Proteobacteria,such

How is it possible for humans to use some Proteobacteria,such as Geobacter species,to generate electricity?

A) Geobacter species use lipopolysaccharide, or LPS, within their outer membrane to store energy that can be harnessed.
B) Geobacter species transfer electrons to electrodes in fuel cells because they transfer electrons to iron or magnesium.
C) Geobacter species are heavily flagellated and display swarming behavior that generates electricity.
D) Geobacter species produce gases during fermentation of carbohydrates, and these gases are used in fuel cells.