The intramolecular hydrogen bonding is present in

In which of the following is hydrogen bonding present?

The correct statement/s about Hydrogen bonding is/are:
$A$. Hydrogen bonding exists when $H$ is covalently bonded to a highly electronegative atom.
$B$. Intermolecular $H$ bonding is present in $o$-nitrophenol.
$C$. Intramolecular $H$ bonding is present in $HF$.
$D$. The magnitude of $H$ bonding depends on the physical state of the compound.
$E$. $H$-bonding has a powerful effect on the structure and properties of compounds.
Choose the correct answer from the options given below:

Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?

Explain why,in spite of having nearly the same electronegativity,oxygen forms hydrogen bonding while chlorine does not.

Given below are two statements:
Statement $I$: $o$-Nitrophenol is steam volatile due to intramolecular hydrogen bonding.
Statement $II$: $o$-Nitrophenol has a high melting point due to hydrogen bonding.
In the light of the above statements,choose the most appropriate answer from the options given below: