Based on the English alphabetical order, three of the following four letter-cluster pairs are alike in a certain way and thus form a group. Which letter-cluster pair DOES NOT belong to that group?
(Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.)​

Logic: 1st letter - 7 = 3rd letter and 2nd letter - 10 = 4th letter

Now, we check each options.

Option (a): GE – ZU (Follow)

G - 7 = Z, E - 10 = U

Option (b): PN – JD (Not Follow)​

P - 7 $$\neq$$​ J, N - 10 = D

Option (c): LJ – EZ (Follow)​

L - 7 = E, J - 10 = Z

Option (d): QO – JE (Follow)​

Q - 7 = J, O - 10 = E

Thus, correct option is (b).