The second number in the given number-pairs is obtained by performing certain mathematical operation(s) on the first number. The same operation(s) is/are followed in all the number-pairs, except one. Find that odd number-pair.

9 : 64

The logic followed here Is :

Add 1 in  Ist number

Then square of that number and you will get the second  number

option 1       3 : 16

                  3+1 = 4

                  4² = 16

option 2          6 : 49

                    6 + 1 = 7

                     7² = 49

option 3      12 : 169

                12 +1 = 13

                  13² = 169

option 4        9 : 64

                   9 +1 = 10

                  10²  = 100