Four letter-cluster pairs have been given, out of which three are alike in some manner and one is different. Select the one that is different.

The logic followed here is:

Logic: First arranging vowels in sequence then arranging consonants in sequence. 

Option 1) IBUOS : IOUBS 

Here, it follow the pattern: First arranging vowels in sequence then arranging consonants in sequence. 

Option 2) HETYD : EDHTY

Here, it follow the pattern: First arranging vowels in sequence then arranging consonants in sequence

Option 3) OEIYZ : IYEOZ

Here, doesn't follow the pattern. 

Option 4) ANHRT : AHNRT

Here, it follow the pattern: First arranging vowels in sequence then arranging consonants in sequence

Hence, the correct answer is "Option 3".