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.)

Logic: 1st letter + 5 = 2nd letter and 2nd letter - 7 = 3rd letter

Now, we check each options.

Option (a): RWP (Follow)

R + 5 = W and W - 7 = P

Option (b): JOH (Follow)​

J + 5 = O and O - 7 = H

Option (c): NSL (Follow)​

N + 5 = S and S - 7 = L

Option (d): PUL (Not Follow)​

P + 5 = U and U - 7 $$\neq$$​ L

Thus, correct option is (d).