Correct Answer - Option 4 :
63 : 29
In all the pairs except 63: 29, the difference between the two numbers can be divided by 7.
Let’s check each option
1) 43 : 22 = 43 - 22 = 21 ÷ 7 = 3
2) 65 : 30 = 65 - 30 = 35 ÷ 7 = 5
3) 29 : 15 = 29 - 15 = 14 ÷ 7 = 2
4) 63 : 29 = 63 - 29 = 34 ÷ 7 = Not divisible by 7
Hence, 63 : 29 is the correct answer.