Organic chemistry?

I have this problem for example Which of the following is most acidic?
A) malonic ester
B) ethyl acetate
C) acetaldehyde
D) acetone
E) acetoacetic ester
so in order to answer it I think i must be able to figure out how to compare acidity between carbonyl compounds but I dont know how. Could you please help me, thank you so much

Comments on "Organic chemistry?"