Sometimes ortho and para isomers of methyl nitrobenzoate are formed in minor amounts, with the ortho isomer being preferred. Explain why the ortho isomer should be disfavoured based on steric effects, and why it might be preferred based on resonance arguments. Use proper structures and notation to show resonance relationships. The ortho isomer has a smaller Rr value than the meta isomer, and the para isomer has a larger Rr value than the meta isomer. Explain these Rr value relationships based on the polarities of the isomers.