Select the term from among the given options that can replace the question mark (?) in the following series.
AsT, cQv, EoX, ?, IkB

The terms are AsT, cQv, EoX, ?, IkB

If you see the first term, that is AsT

First element is A, second element is s and third element is T.

If you see the second term, that is cQv

First element is c, second element is Q and third element is v.

We see that the first element of both terms follows a relation that is first term + 2

A+2 = c (Capital letter turns into the small letter and element is added by 2)

Similarly, for the second element, the relation is the first term - 2

s - 2 = Q (small letter turns into the capital letter and element is subtracted by 2)

Similarly, for the third element, the relation is first term + 2

T + 2 = v (Capital letter turns into small letter and element is added by 2)

So, the term after EoX will be

E + 2 = g

o -2 = M

X +2 = z

Thus, gMz is the correct answer.