1) d: cyclohexene.
2) b: 1-ethyl-2-methylcyclopentane.
3) a: cyclobuta-1,3-diene.
4) b: 4-methylcyclohex-1-ene.
5) b: 5-3thyl-6-methylcyclohepta-1,3-diene.
6) a: 4-ethyl-e-methylcyclopent-1-yne.
7) b: 4-ethyl-1,2-dimethylcyclohexane.
8) c: 8-ethyl-3-methylcycloocta-1-en-4-yne.
9) b: diclohexylmethane.
10) d: 1-ethenyl-2-ethylcyclohexane.