${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{I} + \mathrm{KOH}\left(\mathrm{aq}\right) \to {\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH} + \mathrm{KI}$

The above reaction is an example of -

1. Nucleophilic substitution reaction

2. Elimination reaction

3. Addition reaction

4. Electrophilic substitution reaction

Elimination reaction among the following is-

$$\begin{gathered} \left(1\right) {\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br} + {\mathrm{HS}}^{- }\to \\ {\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{SH} + {\mathrm{Br}}^{-} \\ \left(2\right) {\left({\mathrm{CH}}_3\right)}_2\mathrm{C}={\mathrm{CH}}_2 + \mathrm{HCl}\to \\ {\left({\mathrm{CH}}_3\right)}_2 \mathrm{ClC}-{\mathrm{CH}}_3 \\ \left(3\right) {\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br}+ {\mathrm{HO}}^{-}\to \\ {\mathrm{CH}}_2={\mathrm{CH}}_2 + {\mathrm{Br}}^{-}+{\mathrm{H}}_2\mathrm{O} \\ \left(4\right) {\left({\mathrm{CH}}_3\right)}_3\mathrm{C}-{\mathrm{CH}}_2\mathrm{OH} + \mathrm{HBr} \to \\ {\left({\mathrm{CH}}_3\right)}_2{\mathrm{CBrCH}}_2 {\mathrm{CH}}_3 + {\mathrm{H}}_2\mathrm{O} \end{gathered}$$