The Figure Below Is a Diagram of the Inner Mitochondrial

Multiple Choice

The figure below is a diagram of the inner mitochondrial membrane.
How did the protons (H⁺) in this diagram become concentrated on one side of the membrane?

A) The H⁺ were pumped across the membrane by the electron transport chain.
B) The H⁺ were released when ATP phosphorylated a membrane protein.
C) ATP was used to pump the H⁺ across the membrane.
D) Oxygen must release two H⁺ in the intermembrane space before it can move into the matrix.