Answer:
Option A
Step-by-step explanation:
In the inner membrane, the proteins move easily with the help of enzyme
ATP synthase. These photons then starts moving back into the matrix of mitochondria thereby forming proton gradient during the electron transport chain (ETC) with the assistance of enzyme ATP synthase. When the protons flow through the membrane protein ATP synthase they catalyzes and convert ADP to ATP by gaining one extra phosphate ion.
Hence, option A is correct