Final answer:
Temperature does not directly affect the electrical driving force on ions, which is determined by membrane potential, ion concentration gradient, and ion channel diameter.
Step-by-step explanation:
The factor that does NOT directly affect the direction or magnitude of the electrical driving force is temperature (c). The electrical driving force is primarily determined by factors such as membrane potential (the voltage across a membrane), ion concentration gradient (the difference in ion concentration across the membrane), and to a certain extent, the ion channel diameter which can influence how many ions can pass through a channel at any given time. Temperature, while it can affect the rate of diffusion, does not directly influence the direction or strength of the electrical driving force that drives ion movement across cell membranes.