Which of the following is a ‘perquisite’?   

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

WUW, TSV, QQU, NOT, ?

Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series.

k_Imml_mk_mmk_Ikkl_m

Which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?

_1 m_j_m k_ _m k j 1 m_

Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the letter-cluster that is different.

Select the option that is related to the third letter-cluster in the same way as the second letter-cluster is related to the first letter cluster.

Three of the following letter-clusters are alike in some manner and hence form a group. Which letter-cluster does not belong to that group?

Select the letter-cluster that can replace the question mark (?) in the following series. CXB, HUI, MRP, ROW, ?