Which Statement Correctly Describes the Difference Between the Proton Gradient

Multiple Choice

Which statement correctly describes the difference between the proton gradient across the inner mitochondrial membrane and the proton gradient across the thylakoid membrane of chloroplasts?

A) The first creates an electrochemical gradient, while the second produces a mostly chemical gradient.
B) There is no proton gradient across the thylakoid membrane; magnesium ions create the gradient instead.
C) It is generated by an electron transport system in the first case but not the second.
D) It drives the synthesis of ATP in the first case but not in the second.