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

34 : 3 17 : 6 24 : 4 2 : 51

24 : 4

The logic followed here is: Ist number  is the completely divided by second number Hence option 3 is odd as we know 24 ÷ 4 = 6 , other are not divided by second number