If the first letter of all the words is changed to the next letter of the English alphabetical series, how many words will have more than one vowel? (Same or different vowel)

A,B, D,G,K, ––---- .Which is the next letter?

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, ---