The variation of the boiling points of the hydrogen halides is in the order HF > HI > HBr > HCl. What explains the higher boiling point of hydrogen fluoride?

The bond energy of HF molecules is greater than in other hydrogen halides

The electronegativity of fluorine is much higher than for other elements in the group

The effect of nuclear shielding is much reduced in fluorine which polarises the HF molecule

There is strong hydrogen bonding between HF molecules