What happens when maximize box is set to true?

The correct answer is: D. Maximize box becomes visible.

When the maximize box is set to true, the maximize box in the title bar becomes visible. This allows the user to maximize the window by clicking on the maximize box.

The other options are incorrect because:

• Option A is incorrect because the maximize box does not disappear when it is set to true.
• Option B is incorrect because the maximize box is not disabled when it is set to true.
• Option C is incorrect because the maximize box is not enabled when it is set to true.