Which of the following bromides give only ONE constitutional isomer of an alkene on E2 elimination (no rearrangement, E/Z isomers ignored)?

2-Bromo-2-methylpropane gives only 2-methylpropene, 3-bromopentane gives only pent-2-ene (E and Z), and 2-bromo-3,3-dimethylbutane gives only 3,3-dimethylbut-1-ene because C-3 is quaternary. 3-Bromo-3-methylpentane gives two constitutional alkenes, 3-methylpent-2-ene and 2-ethylbut-1-ene.