Explanation:
Ethylene glycol is a diol with the molecular formula C2H6O2. It has two hydroxyl (-OH) groups attached to a carbon chain. The stability of its conformation depends on the orientation of these groups with respect to each other.

The most stable conformation of ethylene glycol is the one in which the two hydroxyl groups are in the gauche orientation. This means that they are oriented 60 degrees apart from each other, and the two OH groups are on opposite sides of the molecule. The gauche orientation is more stable than the anti-orientation because it reduces steric hindrance between the two OH groups.

The other possible conformations of ethylene glycol are:

- Anti: In this conformation, the two OH groups are oriented 180 degrees apart from each other, and are on opposite sides of the molecule. This conformation is less stable than the gauche conformation because it has higher steric hindrance due to the two OH groups being closer to each other.
- Partially eclipsed: In this conformation, the two OH groups are oriented 120 degrees apart from each other, and are partially eclipsed. This conformation is less stable than the gauche conformation because it has intermediate steric hindrance.
- Fully eclipsed: In this conformation, the two OH groups are oriented 0 degrees apart from each other, and are fully eclipsed. This conformation is the least stable because it has the highest steric hindrance between the two OH groups.

Therefore, the most stable conformation of ethylene glycol is the gauche conformation.