Identify the missing letter in the series: Z, Y, X, W, ?

A. V

What comes next in the series: M, N, O, P, ?

A. Q

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

B. H

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

A. U

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

B. H