How many constitutional isomers are there for C₆H₁₂?

From hexane

1. Hex-1-ene
2. Hex-2-ene
3. Hex-3-ene

From 2-methylpentane

1. 2-methylpent-1-ene
2. 2-methylpent-2-ene
3. (2E)-4-methylpent-2-ene
4. (2Z)-4-methylpent-2-ene
5. 4-methylpent-1-ene

From 3-methylpentane

1. 3-methylpent-1-ene
2. (2E)-3-methylpent-2-ene
3. (2Z)-3-methylpent-2-ene
4. 3-methylidenepentane

From 2,3-dimethylbutane

1. 2,3-dimethylbut-1-ene
2. 2,3-dimethylbut-2-ene

From cyclohexane

1. cyclohexene