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

THME, WKJB, ZNGY, CQDV, ?

FTAS

Explanation:

THME, WKJB, ZNGY, CQDV, ?

The logic followed here is :

T → (+3) → W → (+3) → Z → (+3) → C → (+3) → F

H → (+3) → K → (+3) → N → (+3) → Q → (+3) → T

M → (-3) → J → (-3) → G → (-3) → D → (-3) → A

E → (-3) → B → (-3) → Y → (-3) → V → (-3) → S

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