Chemistry - GOC Question with Solution | TestHub

Molecule (III): This is a homocyclic compound (P) containing 15 $\sigma$-bonds (T, odd number) and has a degree of unsaturation of 4 (U) due to the benzene ring.

Molecule (IV): Naphthalene is a homocyclic hydrocarbon (P, Q) with 19 $\sigma$-bonds (T, odd number) and a degree of unsaturation of 7 (U), which is $\ge 4$.

Since (III) matches (P, T, U) and (IV) matches (P, Q, T, U), option (D) is the only correct choice.