Final answer:
Short Tandem Repeat (STR) analysis is the most useful DNA fingerprinting technique to determine the male relatives of King Tut.
Step-by-step explanation:
The most useful DNA fingerprinting technique to determine the male relatives of King Tut would be Short Tandem Repeat (STR) analysis. STR analysis looks for variations in repeated DNA sequences. By comparing the STR patterns between the mummies and King Tut's known DNA, scientists can determine if the mummies share a common male relative.