Correct Answer - Option 1 : 26 : 37
The logic followed here is:
10 : 17, first number is the non prime number and second number is the prime number.
From option 1 -
26 : 37, first number is the non prime number and second number is the prime number. It is follow the logic. So it is correct.
From option 2 -
20 : 32, first number is non prime number and second number is non prime number. It is not follow the logic. So it is not correct.
From option 3 -
35 : 50, first number is non prime number and second number is non prime number. It is not follow the logic. So it is not correct.
From option 4 -
17 : 28, first number is the prime number and second number is the non prime number. It is not follow the logic. So it is not correct.
Hence, "26 : 37" is the correct answer.