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

A. D

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

A. 16

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

A. D

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

A. 16

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

A. Z