Which compound forms the greatest number of hydrogen bonds per molecule in the liquid state?
HOCH2CH2OH\text{HOCH}_2\text{CH}_2\text{OH}HOCH2CH2OH
CH3CH2OH\text{CH}_3\text{CH}_2\text{OH}CH3CH2OH
CH3OCH3\text{CH}_3\text{OCH}_3CH3OCH3
CH3CHO\text{CH}_3\text{CHO}CH3CHO