In a sequence of letters: A, C, E, G, ?, K. What is the missing letter?

B. H

In a series of numbers: 2, 4, 8, 16, ?, 64. What is the missing number?

B. 32

If the pattern is 1, 4, 9, ?, 25, what number should replace the question mark?

A. 16

In the series X, Y, ?, A, B, what letter should replace the question mark?

A. Z

What character should be inserted in the sequence X, Y, ?, A, B, C?

A. Z