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

The logic followed here is:

Hence, 'BCF' is the correct answer.
Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
G _ C T _ X _ T G X _ T _ X C T G _ C T
Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
Q _ P _ M _ A _ T _ Q A _ T M
Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
r _ x l _ q _ _ x _ p q _ e _ l p _
Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.
BKR, DNV, FQZ, ?, JWH
Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.
AU, BO, CI, DE, ?