The correct answer is: D. all above
The internal resistance of a cell is due to the resistance of the electrolyte, the electrode resistance, and the surface contact resistance between the electrode and electrolyte.
The resistance of the electrolyte is due to the ions in the electrolyte. The ions move through the electrolyte to carry the current, and they encounter resistance as they move. The resistance of the electrolyte is higher for electrolytes with higher concentrations of ions.
The electrode resistance is due to the material of the electrode and the surface area of the electrode. The material of the electrode affects the conductivity of the electrode, and the surface area of the electrode affects the amount of current that can flow through the electrode.
The surface contact resistance is due to the contact between the electrode and the electrolyte. The surface contact resistance is higher for electrodes with poor contact with the electrolyte.
The internal resistance of a cell affects the voltage of the cell. The higher the internal resistance, the lower the voltage of the cell.