Answer:
Intermolecular Forces are the principal forces holding ice together.
Other Options are incorrect because,
Dispersion Forces are found in those molecules which are non-polar in nature. While Ice is made up of Water, which is polar in nature.
Electrostatic Attraction are found between two oppositively charged Ions. So, in water there are no Ions.
Sea of Electrons is found between metal atoms. Metal looses valence electron making a sea of electron. Hence, there is no metal atom in Water.
Result:
Intermolecular Forces like Hydrogen Bonding exists between the water molecules.