Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series.

K _ _ MKXZ _ KX _ MK _ ZM

By Trial and Error method,

Option A

K X Z M | K X Z M | K X Z M | K K Z M

The above letters do not form a series. Hence option A is incorrect.

Option B

K M Z M | K X Z M | K X Z M | K X Z M

The above letters do not form a series. Hence option B is incorrect.

Option C

K X X M | K X Z M | K X K M | K X Z M

The above letters do not form a series. Hence option C is incorrect.

Option D

K X Z M | K X Z M | K X Z M | K X Z M

The above letters form a series.

Hence, the correct answer is Option D