Complete the series: a, c, e, g, ?

B. H

What comes next in the series: A, E, I, M, ?

A. O

Identify the missing number in the series: 12, 24, 48, ?, 192.

B. 96

Complete the series: a, c, e, g, ?

B. H

What letter should replace the question mark? x, u, r, o, ?

C. N