what are The stoichiometric coefficients of the following reaction:

a Cu(s) + b H+(aq) + c NO- ⇆ d Cu2+(aq) + e NO(g) + f H2O(l)

A) a = 2; b = 5; c = 3; d = 3; e = 2; f = 4

B) a = 2; b = 8; c = 3; d = 2; e = 2; f = 4

C) a = 3; b = 5; c = 2; d = 2; e = 2; f = 5

D) a = 3; b = 8; c = 2; d = 2; e = 3; f = 4

E) a = 3; b = 8; c = 2; d = 3; e = 2; f = 4

I only could solve it by looking at the answers and trying them, but I wanna know how to do it.