In the sequence: X, Y, Z, A, ?, C. What is the missing letter?

A. B

In the sequence A, B, C, D, ?, F, G, what character should replace the question mark?

A. E

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

A. 16

In the pattern X, Y, Z, ?, A, B, what character should fill the gap?

A. W

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

B. H