The polymer $\begin{array}{*{20}{c}} {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3} \\ {\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\ {{( - CH_2 - C - CH_2 - C - )}_n} \\ {\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\ {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3} \\ \end{array}$ is formed from which monomer unit?

• A
  $CH_2=C(CH_3)_2$
• B
  $CH_2=CH-CH_3$
• C
  $CH_2=CH_2$
• D
  $CH_2=C(CH_3)-C(CH_3)=CH_2$