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

1. A
   The bond energy of $\text{HF}$ molecules is greater than in other hydrogen halides.
2. B
   The effect of nuclear shielding is much reduced in fluorine which polarizes the $\text{HF}$ molecule.
3. C
   The electronegativity of fluorine is much higher than for other elements in the group.
4. D
   There is strong hydrogen bonding between $\text{HF}$ molecules.