What passive and active processes are involved in the electron transport chain?

The electron transport chain occurs in the mitochondria and during the process, electrons are transferred via reduction oxidation reactions coupled with the transfer of proton across the membrane.
The active process that occur in the electron transport chain is the movement of the protons across the inner mitochondria membrane against their concentration gradients. The passive process that occur in the electron transport chain is the natural movement of ions along their concentration gradient.

Active site is where they touch.

According to edgenuity, the answer is c.