We know that when substituents are positioned correctly, they can transmit electronic information through the benzene ring. Using IR spectroscopy, this concept can be discovered and applied. Explain the carbonyl stretching frequencies shown for acetophenone and 4-methoxyacetophenone.

• A. The carbonyl stretching frequency for 4-methoxyacetophenone is lower due to less conjugation.
• B. The carbonyl stretching frequency for 4-methoxyacetophenone is lower due to increase in positive charge density on carbon.
• C. The carbonyl stretching frequency for 4-methoxyacetophenone is lower due to extended conjugation.
• D. The carbonyl stretching frequency for 4-methoxyacetophenone is lower due to inductive effect of methoxy group.

Answer: (C)