A series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series.
FED, HIJ, NML, PQR, VUT, ?

The series consists of 3-letter clusters alternating between reverse and forward alphabetical order:
1. FED: D, E, F in reverse order.
2. HIJ: H, I, J in forward order.
3. NML: L, M, N in reverse order.
4. PQR: P, Q, R in forward order.
5. VUT: T, U, V in reverse order.
6. The next term must be in forward order.

Let's check the position transitions of the first letters:

* $\text{F}(6)\stackrel{+2}{\to }\text{H}(8)$
* $\text{H}(8)\stackrel{+6}{\to }\text{N}(14)$
* $\text{N}(14)\stackrel{+2}{\to }\text{P}(16)$
* $\text{P}(16)\stackrel{+6}{\to }\text{V}(22)$
* Following the $+2,+6,+2,+6$ pattern, the next increment must be $+2$:
$\text{V}(22)\stackrel{+2}{\to }\text{X}(24)$

Starting with 'X' in forward chronological order gives XYZ.