Which statement correctly describes the difference between a polar covalent bond and a nonpolar covalent bond?

a: nonpolar covalent bonds involve sharing of protons whereas polar covalent bonds involve transfer of
protons.

b: nonpolar covalent bonds involve sharing of electrons whereas polar covalent bonds involve transfer of electrons.

c: nonpolar covalent bonds involve sharing of protons whereas polar covalent bonds involve sharing of electrons.

d: nonpolar covalent bonds involve two atoms that have equal electonegativity whereas polar covalent bonds involve two atoms that are unequal in their electronegativity.

e: nonpolar covalent bonds involve two electrons that have equal electonegativity whereas polar covalent
bonds involve two electrons that are unequal in their electronegativity.