Which one gives only one mono substitution product on chlorination

$$\begin{gathered} C{H}_3 \\ I \\ {\mathrm{CH}}_3-\mathrm{C}-{\mathrm{CH}}_2 \\ \mathrm{I} \\ {\mathrm{CH}}_3 \end{gathered}$$

Replaceable hydrogen atoms are present only on 4 primary carbon atoms. Hence. it gives only one mono chloro Substituted product.