Substrates in List I are heated in ethanol (no added base). Match each with the principal substitution product in List II. List I: (P) 1-bromo-1-methylcyclohexane; (Q) bromobenzene; (R) neopentyl bromide, $(\mathrm{CH}{}_3){}_3\mathrm{C}-\mathrm{CH}{}_2-\mathrm{Br}$; (S) 2-bromo-3,3-dimethylbutane. List II: (1) 2-ethoxy-2,3-dimethylbutane; (2) 2-ethoxy-2-methylbutane; (3) 1-ethoxy-1-methylcyclohexane; (4) no substitution product (essentially unreactive).

1. AP-3, Q-4, R-2, S-1
2. BP-3, Q-4, R-1, S-2
3. CP-3, Q-2, R-4, S-1
4. DP-1, Q-4, R-2, S-3