Which of the following is Hofmann exhaustive alkylation?

1. A \(\mathrm{R} \mathrm{CONH}_2 \xrightarrow[\Delta]{\mathrm{Br}_2, \mathrm{KOH}_{(\mathrm{aq})}} \mathrm{R}-\mathrm{NH}_2\)
2. B \(\mathrm{R}-\mathrm{NH}_2 \xrightarrow[\text { excess }]{\mathrm{R}-\mathrm{X}} \mathrm{R}_4 \stackrel{+}{\mathrm{N}} \overline{\mathrm{X}}\)
3. C \(\mathrm{R}_4 \stackrel{+}{\mathrm{N}} \overline{\mathrm{X}} \xrightarrow[\Delta]{\text { moist } \mathrm{Ag}_2 \mathrm{O}}\) Alkene \(+\mathrm{R}_3 \mathrm{~N}\)
4. D \(\mathrm{R} \mathrm{CN} \xrightarrow{\mathrm{Na} / \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}} \mathrm{R} \mathrm{CH}_2 \mathrm{NH}_2\)