What character should replace the question mark in the series: B, D, F, ?, J, L?

B. G

In the series: 1, 4, 9, ?, 25, what number should replace the question mark?

A. 16

What character should replace the question mark in the sequence: A, B, C, ?, E?

A. D

Identify the missing letter in the pattern: X, Y, ?, A, B.

A. Z

What character should fill the blank in the sequence: 2, 4, 6, ?, 10?

A. 8