Select the set in which the numbers are related in the same way as are the numbers of the following set.
17, 85, 425

Here the second number is five times the first number and the third number is the five times the second number.

Option (a) 15, 75, 300

Here the third number is four times the second number which is not as per the given logic. So this will not be the correct answer.

Option (b) 18, 108, 440

Here the second number is six times the first number which is not as per the given logic. So this will not be the correct answer.

Option (c) 21, 105, 525

Second number = $$21\times5$$ = 105

Third number = $$105\times5$$ = 525

This is the correct option as per the given logic.

Option (d) 16, 80, 320

Here the third number is four times the second number which is not as per the given logic. So this will not be the correct answer.