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

​Given Series:
EFG, KLM, QRS, ?

​Logic: Each Letter + 6

E + 6 → K, K + 6 → Q, Q + 6 → W
F + 6 → L, L + 6 → R, R + 6 → X
G + 6 → M, M + 6 → S, S + 6 → Y​

So, WXY is the next term.

Thus, correct option is (c).