Among the four letter-clusters listed, three are alike in some manner and one is different. Select the odd one.

Logic: 
1st and 3rd letter → Increase by +4
2nd and 4th letter → Decrease by -4
A) CPGL
C → G (+4) 

P → L (-4) 
G → K (+4) 
L → H (-4) 
Follows the pattern correctly.
B) NARD
N → R (+4) 
A → W (-4)  (A should go to W, but it should be E)
R → V (+4) 
D → Z (-4)  (D should go to Z, but it should be Z, incorrect based on standard alphabetical reduction)
Does NOT follow the pattern correctly.
C) PWTS
P → T (+4) 
W → S (-4) 
T → X (+4) 
S → O (-4) 
Follows the pattern correctly.
D) AUEQ
A → E (+4) 
U → Q (-4) 
E → I (+4) 
Q → M (-4) 
Follows the pattern correctly.
Conclusion:
CPGL, PWTS, and AUEQ follow the pattern correctly.
NARD does not correctly follow the pattern.

Correct Answer (b) NARD.