Which statements about substitution versus elimination are correct?

1. AWith 2-bromo-2-methylbutane, a bulky base gives more of the Hofmann alkene than a small base does.
2. BWeakly basic nucleophiles such as $\mathrm{N}{}_3{}^{-}$ and $\mathrm{I}{}^{-}$ favour substitution over elimination at secondary carbon.
3. CA polar aprotic solvent increases the nucleophilicity of anions and speeds up SN2 at a primary carbon.
4. DA tertiary halide reacts with ethoxide mainly by SN2.