Of the following lists of electron transport compounds, which one lists them in order from the one containing electrons with the highest free energy to the one containing electrons with the lowest free energy? Note that not all electron transport compounds in the electron transport chain are listed.

a) FMN of Complex I -- Q -- Fe-S of Complex II -- FADH2 -- Fe-S of Complex III -- Cyt c -- Cyt a of Complex IV -- O2
b) FADH2 -- FMN of Complex I -- Fe-S of Complex II -- Q -- Fe-S of Complex III -- Cyt c -- Cyt a of Complex IV -- O2
c) O2 -- Cyt a of Complex IV -- Cyt c -- Fe-S of Complex III -- Q -- Fe-S of Complex II -- FMN of Complex I -- FADH2
d) FADH2 -- FMN of Complex I -- Fe-S of Complex II -- Fe-S of Complex III -- Q -- Cyt a of Complex IV -- Cyt c -- O2