Which represents a state of high energy?
the sodium and potassium gradients across the outer membrane
electrons in co2
nadp+
nad+
electrons in the water molecule

The sodium and potassium gradients across the outer membrane are in a state of high energy,
electrons in co2 are covalently shared and stable
nadp+ and nad+ are both reduced and electrons in water molecule are polar covalently shared.

The answer is overmatching