Identify the letter-pair from among the given options that expresses a relationship most similar to that expressed in the in the following letter-pairs.

yb, ve, tg, ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
N, P, ?, U, X, Z, C, E, H

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
NZ, PB, RE, TI, VN, XT, ?, BI

Find the missing term: AZY, BXW, CVU, DTS, ?, FPO.

What should come in place of the question mark (?) in the given series based on the English alphabetical order?
XZR, UWO, RTL, OQI, ?

What should come in place of the question mark (?) in the given series based on the English alphabetical order?
GBD, IDF, KFH, MHJ, ?

What should come in place of the question mark (?) in the given series based on the English alphabetical order?
DNY, YIT, TDO, OYJ, ?

What should come in place of the question mark (?) in the given series based on the English alphabetical order?
U, ? , I , E, A.