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

GDBY

GDBY ⇒ G → (-3) → D → (-2) → B → (-3) → Y (ODD)

UROL ⇒  U → (-3) → R → (-3) → O → (-3) → L

QNKH ⇒ O → (-3) → N → (-3) → K → (-3) → H

JGDA ⇒ J → (-3) → G→ (-3) → D → (-3) → A