Which of the following transformations are favoured because an aromatic ion is produced?

1. ACyclopenta-1,3-diene treated with a strong base (sodium hydride) to give $\mathrm{H}{}_2$ and the cyclopentadienide ion
2. BCyclohepta-1,3,5-triene reacting with $\mathrm{Ph}{}_3\mathrm{C}{}^{+}$ to give the tropylium ion
3. CCyclopropene treated with a strong base to give the cyclopropenyl anion
4. DCyclopenta-1,3-diene reacting with $\mathrm{Ph}{}_3\mathrm{C}{}^{+}$ to give the cyclopentadienyl cation