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.)

Correct option is A

Let’s check the options:
Logic: Each letter decreased by -3 place in English alphabet.

Option A: SO → ON → Pattern Not Follow
S − 3 = P (not O)
O − 3 = L (not N)
Option B: AW → XT
A − 3 = X
W − 3 = T
Option C: PL → MI
P − 3 = M
L − 3 = I
Option D: TP → QM
T − 3 = Q
P − 3 = M
Thus, the correct option is (A) SO-ON.