Identify the missing letter in the series: Z, X, V, T, ?

D. U

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

A. O

What is the next letter in the series: A, C, E, G, ?

B. H

Identify the missing letter in the series: Z, X, V, T, ?

D. P

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

A. O