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 - 4 = 3rd letter and 2nd letter + 3 = 4th letter

Now, we check each options.

Option (a): KW – GZ (Follow)

K - 4 = G, W + 3 = Z

Option (b): SQ – OT (Follow)​

S - 4 = O, Q + 3 = T

Option (c): CC – YF (Follow)​

C - 4 = Y, C + 3 = F

Option (d): YM – TH (Not Follow)​

Y - 4 $$\neq$$​ T, M + 3 $$\neq$$​ H

Thus, correct option is (d).