Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the letter-cluster that is different.

SYDJ

THE LOGIC;

1) PVBH,

P → (+6) → V → (+6) → B → (+6) → H

2) CIOU,

C → (+6) → I → (+6) → O → (+6) → U

3) SYDJ,

S → (+6) → Y → (+5) → D → (+6) → J

4) KQWC,

K → (+6) → Q → (+6) → W → (+6) → C

Thus, SYDJ is the odd one.