The benzyl cation $\mathrm{C}{}_6\mathrm{H}{}_5\mathrm{CH}{}_2{}^{+}$ is much more stable than the ethyl cation $\mathrm{CH}{}_3\mathrm{CH}{}_2{}^{+}$ mainly because:

1. Athe cationic carbon is $s{p}^3$ hybridised
2. Bthe positive charge is delocalised into the benzene ring by resonance
3. Cphenyl is a strongly electron-withdrawing group by $-I$ effect
4. Dthe benzyl cation is aromatic because of the $\mathrm{CH}{}_2{}^{+}$ group alone