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

Correct option is A

The pattern for each letter position in the series:
First letters: K → M → O → Q → S (Each letter moves 2 steps forward in the alphabet).
Second letters: A → C → E → G → I (Each letter moves 2 steps forward).
Third letters: B → D → F → H → J (Each letter moves 2 steps forward).
Fourth letters: L → N → P → R → T (Each letter moves 2 steps forward).
Thus, the letter cluster following QGHR is SIJT.
Correct answer is (a) SIJT.