\textbf{234 –} The sum of stoichiometric coefficients of substances in the oxidation–reduction reaction below is how much, and in the half-reaction of reduction, how many moles of electrons are transferred per mole of oxidizing agent? (Options are from right to left.)
$$\mathrm{Ag(s) + NO_3^-(aq) + H^+(aq) \rightarrow Ag^+(aq) + NO(g) + H_2O(l)}$$
(1) 3 , 14 \quad (2) 4 , 14 \quad (3) 4 , 15 \quad (4) 3 , 15