Final answer:
The extent to which each ion contributes differently to membrane potential is dependent upon its membrane permeability.
Step-by-step explanation:
The extent to which each ion contributes differently to membrane potential is dependent upon its membrane permeability. Membrane potential is the voltage across the plasma membrane which is caused by a separation of opposite charges. The active transport of ions across the membrane establishes an electrical gradient. This difference in charges causes a voltage across the membrane, and the movement of ions across the membrane depends on the membrane's permeability to those ions. Therefore, the answer to your question is Option B) Membrane permeability.