Verbal Reasoning - Mental Ability Questions

In a family, there are six members A, B, C, D, E and F. 

A and B are a married couple, A being the male member. D is the only son of C, who is the brother of A. E is the sister of D. B is the daughter-in-law of F, whose husband has died. How is F related to C ? 

In each of the following questions find out the alternative which will replace the question mark.

Zenith : Nadir :: ?:?

In the following question, select the related number from the given alternatives.

43 : 70 : : 94 : ?

If 70!10 = -7, 70!5 = -14 and 40!4 = -10, then find the value of 20!2 = ?

Select the related word/letters/number from the given alternatives.

MN : NM : : JK : ?

Insert the missing character marked as '?'.

When Anuj saw Manish, he recalled, "He is the son of the father of my daughter." Who is Manish ? 

Select the related word/letters/numbers from the given alternatives:

Air:Bird::Water: