Which compound forms the greatest number of hydrogen bonds per molecule in the pure liquid state?
HOCH2CH2OH\text{HOCH}_2\text{CH}_2\text{OH}HOCH2CH2OH
HOCH2CH(OH)CH2OH\text{HOCH}_2\text{CH(OH)CH}_2\text{OH}HOCH2CH(OH)CH2OH
CH3CH2CH2OH\text{CH}_3\text{CH}_2\text{CH}_2\text{OH}CH3CH2CH2OH
CH3COCH3\text{CH}_3\text{COCH}_3CH3COCH3