billnotgatez, sorry about that! new to the forum!
kamiyu and anyone else, would you mind looking at my reasoning.
For A, the oxygen is more electronegative than the carbon (would it be correct to call that double bond polar?) so it draws electron density away from that carbon. The resonance structure for this molecule, with a single bond between C and O, makes this even more apparent.
For B, there is a resonance structure which gives the top carbon a -1 formal charge. I'm not sure how to deal with the central carbon though.
For C, there are no resonance structures, but no additional electron-withdrawing groups compared to the other molecules either. I guess in all three molecules the central carbon is having some of its electron density drawn away by the nitrogen?
where do I go from here - total beginner, thanks for your patience!