1-butanol - Presence of a hydroxyl group attached to the carbon chain makes it a polar molecule. What forces are associated with polar molecules? Is there anything special about the -OH bond that you can think of?
Ethyl Acetate - This is an ester with the presence of a carbonyl group (C=O) making it a polar molecule as well. Also don't forget about the presence of the oxygen atom embedded in the molecule. (However, its boiling point is nothing compared to ethanol. What don't esters have that alcohols do?)
Methyl ethyl ketone - Again it's a polar molecule. Try using similar reasoning as above.