Identify the missing letter in the series: z, x, v, t, ?

C. Q

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

A. U

Complete the series: x, u, r, o, ?

A. L

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

B. H

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

A. U