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

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

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it? 

_cca_a_ca_ac_ab

Directions : Study the following alphanumeric series carefully and answer the questions given below:

12AIFR                  42 WBOL                             63EOCN                15TVMR               75GYTR

How many meaningful words can be formed from the letters of the words which are attached with the numbers in which At least one digit is even digit in the given alphanumeric series?

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

abCD, fgHI, ?, stUV, abCD

Which letter-cluster will replace the question mark (?) to complete the given series?
DRBZ, ABKX, ?, UVCT, RFLR

Which letter should be 7th to the right of the 12th letter from left, if first half of the alphabet series is reversed?

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

LE, OJ, UO, DT,?