Which of the following molecules is expected to form hydrogen bonds in the pure liquid or solid phase: ethylene glycol (HOCH2CH2OH), formaldehyde (H2CO), and dimethyl ether (CH3OCH3)?
a) ethylene glycol only
b) formaldehyde only
c) dimethyl ether only
d) ethylene glycol and formaldehyde
e) ethylene glycol, formaldehyde and dimethyl ether