Four pairs of numbers have been given, out of which three are alike in some manner, while one is different. Choose out the odd one.

798 : 897 : 798 564 : 645 : 456 432 : 324 : 231 321 : 213 : 123

432 : 324 : 231

1) 798 : 897 : 798, 7, 8, 9 are present in all the numbers. 2) 564 : 645 : 456, 5, 6, 4 are present in all the numbers. 3) 321 : 213 : 123, 3, 2, 1 are present in all the numbers. Thus, the 432 : 324 : 231 is the odd one.