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

16 - 49 48 - 81 25 - 36 64 - 100

48 - 81

option 1        16 - 49                      42 - 72   option 2        48 - 81          not square - 92   (odd)   option 3        25 - 36                      52 - 62   option 4       64 - 100                      82 - 102