Verbal Reasoning - Mental Ability Questions

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

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

EF, GI, IL, KO, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
1, 7, 42, 210, 840, ?

Select the missing number from the given responses.

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

ijk, mno, lmn, pqr, opq,?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

GLN, HNQ, IPT, JRW, ?

From the given alternatives, select the word which CANNOT be formed using the letters of the given word.

Resources

From the given alternative words, select the word which cannot be formed using the letters of the given word:

ELABORATE