Which letter-cluster will replace the question mark (?) to complete the given series?
BELL, CGIH, ?, EKCZ, FMZV

Correct option is B

given Series: BELL, CGIH, ?, EKCZ, FMZV
​Step 1: Analyze the changes between consecutive letter clusters
1.BELL → CGIH
· B → C: +1 (Next letter in the alphabet)
· E → G: +2 (Two letters ahead)
· L → I: -3 (Three letters back)
· L → H: -4 (Four letters back)
2.CGIH → ?
· The pattern seems to involve consistent shifts:
· C → D: +1 (Next letter in the alphabet)
· G → I: +2 (Two letters ahead)
· I → F: -3 (Three letters back)
· H → D: -4 (Four letters back)
So, applying this logic, the next letter-cluster should follow the same shifts:
For checking next term.
D→ E: +1 (Next letter in the alphabet)
I → K: +2 (Next letter in the alphabet)
F → C: -3 (Next letter in the alphabet)
D → Z: -4 (Next letter in the alphabet)
The correct letter-cluster that completes the series is(b) DIFD.