C. Oxygen has a different attraction for electrons in H2O than in CO2
the covalent bond between Hydrogen-Oxygen and Carbon-Oxygen is different because the difference of electronegativity (the tendency of an atom to attract a shared pair of electrons towards itself) between Hydrogen and Oxygen is a lot higher than the difference of electronegativity between Carbon and Oxygen. This difference in electronegativity results in separation of partial electric charge creating polar bonds and giving the molecule a polarity.