Which letter-cluster will replace the question mark (?) to complete the given series?
 ERKV, HYVK, ?, NMRO, QTCD

Which letter-cluster will replace the question mark (?) to complete the given series?
 TBNF, CJUL, LRBR, UZIX, ?

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

ACFD, CFHG, ?, GLLM, IONP

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

REV, UXD, XQL, AJT, ?

Which letter cluster will replace the question mark (?) to complete the given series?
 ETRE, AZJG, WFBI, SLTK, ?

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

TYG, ?, PSM, NPP, LMS

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

AVTE CTRG ERPI GPNK   ?

Which of the following numbers will replace the question mark (?) in the given series?
 4, 6, 12, 14, 28, 30, ?