In order to protect iron from corrosion, which one will you prefer as a sacrificial electrode, Ni or Zn? Why?
a) Zn, because it has a higher electrode potential than Ni.
b) Ni, because it has a lower electrode potential than Zn.
c) Zn, because it forms a more stable oxide layer than Ni.
d) Ni, because it reacts more readily with oxygen than Zn.