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

A. I

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

A. I

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

A. R

What letter should replace the question mark in the series: z, x, v, t, ?

A. R

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

B. H