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

Now, we check each options.

Option (a): IT - PR (Not Follow)

I + 2 $$\neq$$​ P, T + 2 $$\neq$$​ R

Option (b): EH - GJ (Follow)​

E + 2 = G, H + 2 = J

Option (c): QT - SV (Follow)​

Q + 2 = S, T + 2 = V

Option (d): TW - VY (Follow)​

T + 2 = V, W + 2 = V

Thus, correct option is (a).