Based on the English alphabetical order, three of the following four letter-clusters are alike in a certain way and thus form a group. Which letter-cluster 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.)

From the given options —

Logic: +2 and -5
E (5) + 2 = G (7)
G (7) - 5 = B (2)
(b) PMJ
P (16) - 3 = M (13)
M (13) - 3 = J (10)
(c) JLG
J (10) + 2 = L (12)
L (12) - 5 = G (7)
(d) SUP
S (19) + 2 = U (21)
U (21) - 5 = P (16)
Observation:
All clusters except option (b) follow the pattern: +2, then -5
Option (b) follows: -3, then -3

Correct answer is (b)