Identify the missing letters in the series: a, e, i, o, ?

A. U

What letter comes next in the series: d, g, j, m, ?

A. P

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

B. H

What letter should replace the question mark in the series: m, n, p, q, ?

A. R

Identify the missing letters in the series: a, e, i, o, ?

A. U