The answer is: A. in a polar bond, electrons are shared unequally.
For example, in water (H₂O), atoms of hydrogen (H) and oxygen (O) are connected by polar covalent bonds. Electrons are closer to oxygen, because it has greater electronegativity.
Covalent bond is bond between nonmetals. Hydrogen and oxygen are nonmetals.
Another example, covalent compound ammonia (NH₃) is made of two nonmetals: hydrogen and nitrogen (N).
Electronegativity (χ) is a property that describes the tendency of an atom to attract a shared pair of electrons. Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.
When the electronegativity difference is greater, the bond polarity is increasing.
