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

A. D

In the pattern A1, B2, C3, ?, E5, what should replace the question mark?

A. D4

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

C. F

In the series: 2, 4, 8, ?, 32, what number should replace the question mark?

B. 16

What character should replace the question mark in the pattern: 1, 1, 2, 3, ?, 13?

B. 8