Complete the series: B, D, F, H, ?

A. J

What letter comes next in the series: M, O, Q, S, ?

A. T

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

A. R

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

C. U

Complete the series: B, D, F, H, ?

D. I