Which is the next letter of the series?

W, U, R, N, I

The next letter chain is :

BIP, CJQ, DKR, ...............

What is the next letter of the series F, I, L, O, ...........?

Find the next letter in the sequence A,D,I,P, ---

Fill up the next letter in the particular series B,C,E,G,K,M, -----

Find the next letter in the sequence
A, D, I, P, ……