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

A. J

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

A. Q

What letter comes next in the series: d, g, j, m, ?

A. P

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

A. R

Identify the missing letter in the series: m, n, o, ?, q, r

A. P