What character should be inserted in the sequence: 2, 4, 6, ?, 10?

B. 8

In the pattern: X, Y, Z, ?, B, what character is missing?

A. A

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

A. B

Identify the missing letter in the pattern: A, C, E, ?, I.

A. G

Identify the missing character in the series 1, 4, 9, ?, 25, 36.

A. 16