Solvents are: water, DMSO, hexane, methanol. Which pair correctly names the solvent giving the fastest ${\mathrm{S}}_{\mathrm{N}}1$ solvolysis of $(\mathrm{CH}{}_3){}_3\mathrm{C}-\mathrm{Cl}$ and the solvent giving the fastest ${\mathrm{S}}_{\mathrm{N}}2$ reaction of $\mathrm{CH}{}_3\mathrm{Br}$ with $\mathrm{NaCN}$ (among these four that dissolve the salt)?

1. A${\mathrm{S}}_{\mathrm{N}}1$: hexane; ${\mathrm{S}}_{\mathrm{N}}2$: methanol
2. B${\mathrm{S}}_{\mathrm{N}}1$: water; ${\mathrm{S}}_{\mathrm{N}}2$: DMSO
3. C${\mathrm{S}}_{\mathrm{N}}1$: DMSO; ${\mathrm{S}}_{\mathrm{N}}2$: water
4. D${\mathrm{S}}_{\mathrm{N}}1$: water; ${\mathrm{S}}_{\mathrm{N}}2$: methanol