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

B. H

What letter completes the series: z, x, v, t, ?

C. Q

Find the missing letter in the series: b, d, f, h, ?

A. J

Find the missing letters in the series: b, d, f, h, ?

A. J

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

A. R