Certain Complexes of the Mitochondrial Electron Transport Chain Pump Protons

Certain complexes of the mitochondrial electron transport chain pump protons. Which of the following BEST describes the movement of protons in this situation?

A) across the outer mitochondrial membrane, from the cytoplasm to the intermembrane space
B) across the outer mitochondrial membrane, from the intermembrane space to the cytoplasm
C) across the inner mitochondrial membrane, from the intermembrane space to the matrix
D) across the inner mitochondrial membrane, from the matrix to the intermembrane space