Explanation:

Let's analyze the given series:

- 485 : 25

- ? : 21

- 401 : 23

Let's look for the relationship between the numbers:

- 485 - 460 = 25

- 401 - 378 = 23

The second number is the difference with a "base" number.

Try with 21:

- 21 less than what gives an option in your list?

Try each option:

- 246 - 225 = 21

- 325 - 304 = 21

- 346 - 325 = 21

- 225 - 204 = 21

Now, looking at the pattern with the chosen base numbers:

- 485 is 25 more than 460

- 401 is 23 more than 378

The pattern is about subtracting 25, 23, 21 from the first number to get a 460, 378, and so on.

But let's connect the numbers to your options:

For ? : 21, if we reverse the logic:

- ? - 21 = base

If we arrange as above, the correct option among your choices that fits:

- 246 - 21 = 225

So, the correct choice is:

- Option 1: 246

Summary:

- The relationship is: first number minus corresponding second number = base number.

- Matching this logic, Option 1 (246 : 21) fits the pattern just like the other pairs.

- 246 - 21 = 225

So, the answer is:

Option 1: 246