On heating in ethanol (no added base), which of the following bromides give a substitution product whose carbon skeleton or substituent position has changed through a carbocation rearrangement?

Option 1: methyl shift from the quaternary carbon converts the secondary into a tertiary cation. Option 3: the primary neopentyl system ionises with methyl migration to the tertiary $(\mathrm{CH}{}_3){}_2\mathrm{C}{}^{+}\mathrm{CH}{}_2\mathrm{CH}{}_3$. Option 4: the cation $\mathrm{CH}{}_3\mathrm{CH}{}^{+}-\mathrm{C}(\mathrm{CH}{}_3){}_2\mathrm{Et}$ rearranges by methyl shift to the tertiary cation. Option 2 already gives a tertiary cation, so no shift occurs.