Why does the 13C NMR show five different types of carbon atoms when the molecular formula indicates the compound contains seven carbon atoms?
a. Only the carbon atoms that are attached to a hydrogen atom show a absorption.
b. There should only be three peaks in the 13C NMR, so the compound must contain impurities.
c. The ortho and meta carbons of the ring are equivalent.
d. There are only five carbon atoms in this molecule. The molecular formula is a mistake.