Three of the following four letter-cluster pairs are alike in a certain way and thus form a group. Which is the letter-cluster pair that does NOT belong to that group?
(Note: The odd one out is not based on the number of consonants/vowels or their positions in the letter-cluster.)

A.) EJ - OT:  E(5)+5=J(10), O(15)+5=T(20)

B.) PF - OI: P(16)+5=U(21), O(15)+5=T(20) Not Follows

C.) KP - UZ: K(11)+5=P(16), U(21)+5=Z(26)

D.) ​CH - MR: C(3)+5=H(8), M(13)+5=R(18)

All options are follow the same pattern except option B

Hence B is not belong to that group.