Find the missing number?

Which number replaces the question mark?

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

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.
COT, DQU, ESV, FUW, ?

In the following question, select the missing number from the given series.

Find the missing number?

Study the given pattern carefully and select the number that can replace the question mark(?) in it.