Out of $o$-nitrophenol and $p$-nitrophenol,which is more volatile?

(A) $o$-Nitrophenol is more volatile because of intramolecular $H$-bonding (chelation),whereas intermolecular $H$-bonding is present in $p$-nitrophenol.
Thus,$p$-nitrophenol is associated with other molecules through $H$-bonding,which results in a higher boiling point compared to $o$-nitrophenol.