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.)​

Form the given options : -

Logic: 1st letter +7 and 2nd letter -5

A. BK – IF
B = 2 → I = 9 (+7)
K = 11 → F = 6 (−5)
B. HQ – OL
H = 8 → O = 15 (+7)
Q = 17 → L = 12 (−5)
C. TC – AY
T = 20 → A = 1 (−19)
C = 3 → Y = 25 (+22 or -4) False.
D. PY – WT
P = 16 → W = 23 (+7)
Y = 25 → T = 20 (−5)
Correct answer is (C) does not follow this pattern