Eight persons- A, B, C, D, E, F, G and H are sitting around a square table but not necessarily in the same order. Four persons are sitting at the corner of the table facing outside the centre while four persons are sitting on the middle side of the table facing inside the centre.

D sits adjacent to F.
Two persons sit between D and A.
A sits third to the right of H.
H does not sit at the corner of the table.

F sits second to the left of C.
Two persons sit between C and E.
Thus, Case 1 gets cancelled.

G does not sits adjacent to H.

This is the final arrangement.
Three persons sit between B and C when counted from the left of C.