Select the letter-cluster that can replace the question mark (?) in the following series.
BIN, CJO, DKP, ?

Correct option is A

Given series: BIN, CJO, DKP, ?
First letters: B → C → D → ?
The letters are increasing by 1 position in the alphabet: B (2) → C (3) → D (4).
The next letter should be E.
Second letters: I → J → K → ?
The letters are increasing by 1 position: I (9) → J (10) → K (11).
The next letter should be L.
Third letters: N → O → P → ?
The letters are increasing by 1 position: N (14) → O (15) → P (16).
The next letter should be Q.
Thus, the next letter-cluster in the series is ELQ.
The correct letter-cluster is (a) ELQ.