A. CH2=CH-OCH2CH3 is a polar molecule due to the presence of the C=O and C-O bonds, which are polar. The net molecular dipole moment would point from the oxygen atom to the hydrogen atoms.
B. CO2 is a non-polar molecule because the two oxygen atoms are symmetrically placed around the carbon atom, which creates a cancellation of the individual bond dipoles. So, CO2 doesn't have any molecular dipole moment.