When an isomer Y with molecular formula $\text{C}_4\text{H}_9\text{Br}$ is hydrolysed in aqueous alkali to give an alcohol $\text{C}_4\text{H}_9\text{OH}$, the reaction rate is observed to remain unchanged when the concentration of $\text{OH}^-$ ions present is altered. Which molecular structure is most likely to be Y?
- A$\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{Br}$
- B$\text{CH}_3\text{CH}_2\text{CHBrCH}_3$
- C$(\text{CH}_3)_2\text{CHCH}_2\text{Br}$
- D$(\text{CH}_3)_3\text{CBr}$