Correct Answer: JHMX

Solution : Let's check the options–
First option: AKWE; The vowels A and E are present in the letter cluster.
Second option: PNTO; The vowel O is present in the letter cluster.
Third option: LCUF; The vowel U is present in the letter cluster.
Fourth option: JHMX; There is no vowel present in the letter cluster.

So, all the options have at least 1 vowel except the fourth option. Hence, the fourth option is correct.