Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.

DW. HS, LO, PK, ?

Given: DW. HS, LO, PK, ?

Logic: First letter increases by +4 and second letter is opposite letter of first letter.

First letter: D+4=H, H+4=L, L+4=P, P+4=T

Second letter: D-W (opposite letter of D), H-S (opposite letter of H), L-O (Opposite letter of L), P-K (opposite letter of P), T-G (Opposite letter of G).

So, ? is replaced by TG

Thus, Option C is the correct answer.