i) There are 9 friends A, B, C, D, E, F, G, H seated in a circle...

To determine which pair may not be seated adjacent to each other, we evaluate the established seating chain: C-A-H-E-B-F. - AH: Explicitly stated as adjacent in the rules. - EB: Since $B$ is (2^{\text {nd }}) to the right of $H$, and $E$ is (3^{\text {rd }}) to the right of $C, E$ must sit between $H$ and $B$, making them adjacent. - DC: $D$ is part of the $D G$ pair. This group sits in the remaining section with an unknown 9th person. Because their order is not fixed, $D$ is not necessarily next to $C$. Final Answer: (B) DC