Generally, How Do Compounds Such as Rotenone and Cyanide Inhibit

Generally, how do compounds such as rotenone and cyanide inhibit the electron transport chain?

A) They block electron transfer downstream from the inhibitor-bound enzyme.
B) They absorb electrons.
C) They are acidic.
D) They inhibit the production of proteins involved in the electron transfer chain.
E) They increase the rate of electron transfer.