Explanation:

To identify the correct number that completes the series, let's break down the sequence:

- 578 to 577: A decrease of 1.

- 577 to 568: A decrease of 9.

- 568 to 543: A decrease of 25.

Notice the pattern of decreases:

- 1 (1^2)

- 9 (3^2)

- 25 (5^2)

It seems the decreases are following a pattern of consecutive odd squares (1^2, 3^2, 5^2).

- The next decrease should be the next odd square: 7^2, which is 49.

Now, subtract 49 from 543:

- 543 - 49 = 494.

So, the number that should replace the question mark is 494.

- 528: Incorrect decrease pattern.

- 518: Incorrect decrease pattern.

- 532: Incorrect decrease pattern.

- 494: Follows the predicted pattern correctly.

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