All the other compounds listed among the options are capable of forming hydrogen bonds with water except CH3CH2CH2F.
Recall that hydrogen bonds are formed when hydrogen is directly bonded to a highly electronegative atom such as nitrogen, oxygen, fluorine, sulphur, et cetra.
Such bonds are not present in CH3CH2CH2F, rather fluorine is bonded to carbon to give a halogenoalkane. This compound will display the least solubility in water.
