Which of the four options will replace the question mark (?) in the following series? UE 88, VG 84, WI 80, XK76, ?

The correct option is YM72.

To find the term that replaces the question mark (?), let us analyze the pattern by breaking each term in the series down into three separate components: the first letter, the second letter, and the number.

1. First Letter Sequence:
The first letters of the terms are U, V, W, and X. These letters follow consecutive alphabetical order:
$U\to V\to W\to X\to Y$
Thus, the first letter of the next term is Y.

2. Second Letter Sequence:
The second letters are E, G, I, and K. Let us look at their respective positions in the English alphabet:
E is the 5th letter, G is the 7th, I is the 9th, and K is the 11th.
$5\to 7\to 9\to 11$
The positions increase by 2 in each consecutive term. Following this pattern, the next position is:
$11+2=13$
The 13th letter of the alphabet is M. Therefore, the second letter of the next term is M.

3. Number Sequence:
The numbers in the terms are 88, 84, 80, and 76. Let us look at the differences between successive numbers:
$88-4=84$
$84-4=80$
$80-4=76$
The sequence decreases by 4 at each step. Following this arithmetic progression, the next number is:
$76-4=72$
Thus, the number part of the next term is 72.

Combining the three components together, we get YM72.