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

121 : 16

option 1         81 :12

                   9² = 81

                  9 + 3 = 12

option 2         64 : 11

                   8² = 64

                  8 + 3 = 11

option 3         100 :13

                   10² = 100

                  10 + 3 = 13

option 4        121 : 16

                  11² = 121

                  11+ 3 = 14 but 16 is given (odd)