Correct option is C
Logic:
The number of letters skipped in between the adjacent letters in the series are multiples of 3.

Lets check by options:
Option (a): GKOTZ

Not follow pattern.
Option (b): LORUX

Not follow pattern.
Option (c): AELPZ

Follow this pattern.
Option (d): DHLPU

Not follow pattern.
Thus, the correct answer is (c).