Option B proceeds through an electrophilic substitution reaction.

$\mathrm{C}{\mathrm{l}}_2$ reacts with $\mathrm{A}\mathrm{l}\mathrm{C}{\mathrm{l}}_3$ to form $\mathrm{C}{\mathrm{l}}^{+}$ and ${\left[\mathrm{A}\mathrm{l}\mathrm{C}{\mathrm{l}}_4\right]}^{-}.$ This $\mathrm{C}{\mathrm{l}}^{+}$ attaches the molecule making it electrophilic substitution.

Option A is nucleophilic addition.

Option C is an addition reaction.

Option D is nucleophilic substitution.