Select the option that is related to the third number in the same way as the second number is related to the first  number and the sixth number is related to the fifth number.

8: 128 :: 6 : ? :: 11  : 242

72

8: 128 :: 6 : ? :: 11  : 242

The logic followed here is :

Ist number² × 2 = IInd number

AS

8: 128

8² × 2

= 64  × 2

= 128

and

11  : 242

11² × 2

= 121  × 2

= 242

Similarly

6 : ?

6² × 2

= 36  × 2

= 72