Which is the lowest energy conformation of butane?

Which of these factors does not govern the stability of a conformation in acyclic compounds?

Given below are two statements:
Statement $I$: There are several conformers for $n$-butane. Out of those conformers,the fully eclipsed conformer (dihedral angle $0^{\circ}$) is the least stable and the anti-staggered conformer (dihedral angle $180^{\circ}$) is the most stable.
Statement $II$: As the dihedral angle increases from $0^{\circ}$ to $60^{\circ}$,torsional strain decreases from the fully eclipsed conformer $(X)$ to the gauche conformer $(Y)$.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following conformations of $n-$butane is the least stable?

The total number$(s)$ of stable conformers with non-zero dipole moment for the following compound is (are):

What will be the stability order in case of ethylene glycol?