Alphabet Test Questions

In the following question, select the related letter/letters from the given alternatives.

CPR : ERT : : DQS : ?

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

In the following question, from the given alternative words, select the word which cannot be formed using the letters of the given word.
Biological

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
A, E, I, M, ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
BT, DR, FP, ?

How many such pairs of letters are there in the word REGIONAL, each of which has as many letters between them in the word (in both forward and backward directions) as they have between them in the English alphabetical series ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series. PR, VX, BD, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
NM, PK, SI, ?