Which of the following terms will replace the question mark (?) in the given series?

WKED, ZLHE, CMKF, FNNG, ?​​

WKED, ZLHE, CMKF, FNNG, ?​​

Logic: 1st letter: +3, 2nd letter: +1, 3rd letter: +3, 4th letter: +1

1st letters: W +3 → Z, Z +3 → C, C +3 → F, F +3 → I
2nd letters: K +1 → L, L +1 → M, M +1 → N, N +1 → O
3rd letters: E +3 → H, H +3 → K, K +3 → N, N +3 → Q
4th letters: D +1 → E, E +1 → F, F +1 → G, G +1 → H

So, IOQH is the next term.

Thus, correct option is (a).