Explanation:

- Start by identifying the relationship in the given pair, 9 : 734.

- 9 squared is 81, 81 multiplied by 9 is 729, adding 5 gives you 734.

- Option 1: 6 : 221

- 6 squared is 36, 36 multiplied by 6 is 216, adding 5 gives you 221.

- Option 2: 4 : 71

- 4 squared is 16, 16 multiplied by 4 is 64, adding 5 gives you 69. This is incorrect.

- Option 3: 8 : 517

- 8 squared is 64, 64 multiplied by 8 is 512, adding 5 gives you 517.

- Option 4: 7 : 348

- 7 squared is 49, 49 multiplied by 7 is 343, adding 5 gives you 348.

- Option 2: 4 : 71 does not follow the pattern.