Select the letter-cluster from among the given options that can replace the question mark (?) in the following series?

KMTC, EVOM, OQXG, lZSQ, ?

SUBK

Explanation:

KMTC, EVOM, OQXG, lZSQ, ?

The logic followed here is :

K → (-6) → E → (+10) → O → (-6) → I → (+10) → S

M → (+9) → V → (-5) → Q → (+9) → Z → (-5) → U

T → (-5) → O → (+9) → X → (-5) → S → (+9) → B

C → (+10) → M → (-6) → G → (+10) → Q → (-6) → K

So, the letter-cluster that replaces the (?) to complete the series is "SUBK"