Find the missing number in the following image.

In the following question, select the number which can be placed at the sign of question mark(?) from the given alternatives.

Direction: In the following question, select the related letters from the given alternatives. 

QDXM : SFYN :: UIOZ : ?

Which number replaces the question mark?

Which numbers replace the question mark

In the following question find out the missing number?

In the following question, select the number which can be placed at the sign of question mark (?) from the given alternatives.

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