Which letter-cluster from the options will replace the question mark (?) to complete the given series?
 ASDF, BUGJ, CWJN, ?

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

QML, PRC, OWT, NBK, ?

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

ABCD, FVJV, KPQN, PJXF, ?

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

ROM, URJ, XUG, AXD, ?

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

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

REV, UXD, XQL, AJT, ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
 NMQR, NQYD, NUGP, NYOB, ?

Which letter-cluster will replace the question mark (?) to complete the given series?
 CZNM, FXOL, IVPK, ?, ORRI