Which statements about amine basicity are correct? ($\mathrm{p}{K}_a$ of conjugate acids in water: $\mathrm{CH}{}_3\mathrm{NH}{}_3{}^{+}$ 10.6, $(\mathrm{CH}{}_3){}_2\mathrm{NH}{}_2{}^{+}$ 10.7, $(\mathrm{CH}{}_3){}_3\mathrm{NH}{}^{+}$ 9.8, $\mathrm{C}{}_6\mathrm{H}{}_5\mathrm{NH}{}_3{}^{+}$ 4.6.)

1. AIn the gas phase the basicity order is $(\mathrm{CH}{}_3){}_3\mathrm{N}>(\mathrm{CH}{}_3){}_2\mathrm{NH}>\mathrm{CH}{}_3\mathrm{NH}{}_2>\mathrm{NH}{}_3$.
2. BIn water, $(\mathrm{CH}{}_3){}_3\mathrm{N}$ is a weaker base than $(\mathrm{CH}{}_3){}_2\mathrm{NH}$ because $(\mathrm{CH}{}_3){}_3\mathrm{NH}{}^{+}$ is less solvated.
3. CAniline is a much weaker base than $\mathrm{CH}{}_3\mathrm{NH}{}_2$ in water because its lone pair is delocalised into the ring.
4. DThe aqueous basicity order of the methylamines is the same as the gas-phase order.