Which letter-cluster will replace the question mark (?) to complete the given series?

CABQ, CEJC, CIRO, CMZA, ?

Which letter-cluster will replace the question mark (?) to complete the given series?

TMT, ZOB, FQJ, LSR, ?

Which letter-cluster will replace the question mark (?) to complete the given series?

FHG, IKJ, LNM, ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
 RTM, VZX, ZFI, DLT, ?

Which letter-cluster will replace the question mark (?) to complete the given series?

HFK, KHM, ?, QLQ, TNS

Which letter-cluster will replace the question mark (?) to complete the given series?

TQT, ZSB, FUJ, LWR, ?

Which letter-cluster will replace the question mark (?) to complete the given series?

MBTN, KCSP, IDRR, ?, EFPV

Which letter-cluster will replace the question mark (?) to complete the given series?

ZXE ZWD ZVC ? ZTA