The hydrides of the first elements in groups $15-17$, namely $NH_3$, $H_2O$ and $HF$ respectively show abnormally high values for melting and boiling points. This is due to

• A
  small size of $N$, $O$ and $F$
• B
  the ability to form extensive intermolecular $H$-bonding
• C
  the ability to form extensive intramolecular $H$-bonding
• D
  effective van der Waals' interaction