The correct energy graduation of different conformers is

Which of the following is the correct order of stability of different conformations of butane ?

Which will be the correct stability order of the different conformations of n - butane ?

Which will be the correct stability order of the different conformations of n - butane ?

Draw Sawhorse and Newman's projections of the different conformers of ethane.

The lowest energy conformer of is:

What are the relative stabilities of different conformations of ethane. Is it possible to isolate these at room temperature?