In the context of membrane potential (voltage measured as $V{m}_{in}-V_{out}$), what does a negative cell voltage indicate?

• A. The membrane has become freely permeable to all ions, eliminating electrical gradients while maintaining chemical gradients.
• B. The outside of the cell is electrically negative relative to the inside.
• C. There is no separation of charge across the membrane (the membrane potential is $0$ mV).
• D. The inside of the cell is electrically negative relative to the outside.

Answer: (D)