Answer:
A. Li-O
Step-by-step explanation:
The highest polarization will occur between the atoms of Li-O because they have the most electronegativity difference between them.
Polarization occurs when there is a separation of charge between the atoms of heteronuclear molecules.
The electronegativity gives the tendency for an atom to attract the electrons within the bond pair to itself.
To know the atom with most polarization, it has to be one with highest electronegativity difference. Li and O have the highest difference. Also, since the bond is between a metal and non-metal, it is obviously the most polarized.