optical isomers

1a) Draw 4 optical isomers of 2-bromo-3-methylpentane

b) Give the name and structure of the major product when it is refluxed with alcoholic potassium hydroxide.

c) Write mechanism for one of the above change.

2a) Show, within 2 steps, how you can prepare cyclohexene from cyclohexane.
Give reagent and condition.

b) Write the mechanism for them.