The diagram illustrates the structure of nylon. Which compounds could be used to make nylon?
- A$\text{HO}_2\text{C--(CH}_2\text{)}_6\text{--CO}_2\text{H}$ and $\text{H}_2\text{N--(CH}_2\text{)}_6\text{--NH}_2$
- B$\text{HO}_2\text{C--(CH}_2\text{)}_4\text{--CO}_2\text{H}$ and $\text{H}_2\text{N--(CH}_2\text{)}_4\text{--NH}_2$
- C$\text{HO}_2\text{C--(CH}_2\text{)}_4\text{--CO}_2\text{H}$ and $\text{H}_2\text{N--(CH}_2\text{)}_6\text{--NH}_2$
- D$\text{HO}_2\text{C--(CH}_2\text{)}_6\text{--CO}_2\text{H}$ and $\text{H}_2\text{N--(CH}_2\text{)}_4\text{--NH}_2$