The boiling point of `p-`nitrophenol is higher than that of `o-`nitrophenol because.
A. `NO_2` group at p-position behave in a different way from that at o-position
B. intramolecular hydrogen bonding exists in p-nitrophenol
C. there is intermolecular hydrogen bonding in p-nitrophenol
D. p-nitrophenol has a higher molecular weight than o-nitrophenol
