What character should replace the question mark in the pattern X, Y, Z, A, B, ?

A. C

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

A. D

What character should replace the question mark in the pattern X, Y, Z, ?, B, C?

A. A

In a pattern of letters: X, Y, Z, A, B, ?, D. What is the missing letter?

A. C

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

B. H