Which of the following, upon treatment with tert- BuONa followed by...

In the options, they have acidic $\beta - H$ so an elimination reaction takes place and alkene will be formed.

And the formed alkene decolourizes the bromine water {$\overset{⊕}{E}$ addition reaction of an alkene by $HOBr$} while in $\left(4\right)$ it does not have $\beta - H$ so, there is no formation of alkene, hence does not decolourize ${Br}_{2}$ water.