Which letter should replace the question mark in the series: B, D, F, H, ?

D. I

What is the next letter in the series: B, E, I, M, ?

A. O

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

B. S

Find the odd one out in the series: A, D, G, J, K

D. K

A, C, E, G, ?

A. I