19. Using valence bond theory, which following statements correctly describe bonding in the nitrate ion (NO₃⁻)? (A) There exist multiple resonance structures. (B) Resonance structures transform rapidly between each other. (C) The nitrogen atom is sp² hybridized. (D) Among all three N-O bonds, one is shorter than the other two. (E) NO₃⁻ has no net dipole moment because the N-O bonds are non-polar.