Select the correct statement about polar bonds and dipole moments. a. A linear diatomic molecule AX has a dipole moment equal to the sum of the electronegativities of A -- X.

b. The dipole moment for a polyatomic molecule equals the vector sum of the individual bond moments.

c. The electrons in a polar covalent bond spend more time near the least electronegative atom in the bond.

d. A polyatomic molecule which contains one or more polar bonds always has a molecular dipole moment.

e. A dipole moment quantifies the separation of charge in a molecule using the number of lone pairs on each atom.