Which of the following options correctly represents the overall reaction in the battery on discharge?
a) Zn(s) + 2H2O(l) → Zn(OH)2(aq) + H2(g)
b) Zn(s) + 2OH-(aq) → Zn(OH)2(s) + 2e-
c) Zn(OH)2(s) + H2(g) → Zn(s) + 2H2O(l)
d) Zn(OH)2(aq) + 2e- → Zn(s) + 2OH-(aq)