A portion of an addition polymer chain is illustrated. $\,-\text{CH}-\text{CH}_2-\text{CH}_2-\text{CH}-\,$ with a $\text{Cl}$ group attached to each $\text{CH}$. Which monomer might have been used to produce this polymer?
- A$\text{CH}_2\text{CHCH}_2\text{Cl}$
- B$\text{CH}_2\text{CHCl}$
- C$\text{CH}_3\text{CHCHCl}$
- D$\text{CHClCH}_2\text{CH}_2\text{Cl}$