For the Electrochemical Cell Ni(s) | Ni²⁺(1 M) || H⁺(1

For the electrochemical cell Ni(s) | Ni²⁺(1 M) || H⁺(1 M) | H₂(1 atm) | Pt(s) , which one of the following changes will cause a decrease in the cell voltage

A) Increase the pressure of H₂ to 2.0 atm.
B) Decrease the mass of the nickel electrode.
C) Lower the pH of the cell electrolyte.
D) Decrease the concentration of Ni²⁺ ion.
E) None of the above.