Final answer:
Assertion (A) is incorrect as the resonance hybrid is more stable and lower in energy than any individual canonical form. Reason (R) is correct, indicating that a resonance hybrid is a composite of multiple resonance forms showing electron delocalization. The correct answer is C, A is not correct but R is correct.
Step-by-step explanation:
The student's question involves understanding resonance and how it applies to the stability and structure of a molecule. Specifically, it's about the comparison of energy in resonance hybrids and canonical forms, and the reason why resonance hybrids cannot be represented by a single structure.
The Assertion (A) claims that the energy of a resonance hybrid is equal to the average of energies of all canonical forms. This is not correct because the resonance hybrid is actually more stable (and thus lower in energy) than any of its contributing canonical forms. It is a more favorable energy state due to electron delocalization.
The Reason (R) is correct; a resonance hybrid cannot be represented by a single structure because it is an average of the resonance forms, indicating the delocalization of electrons across the structure.
Therefore, the correct answer is C. A is not correct but R is correct.