Select the appropriate antonym for the underlined word.

I need to spend some time fixing the disorder of my bookshelves.

Regulate

The correct answer is option 3. Regulate.

In the given sentence, "disorder" refers to a lack of organization or arrangement, indicating that the bookshelves are in a state of confusion or disarray.

The antonym, "Regulate," implies bringing order or control to something. Therefore, in the context of the sentence, if one needs to fix the disorder of the bookshelves, they are likely aiming to bring them into a more organized and regulated state.

Hence, "Regulate" is the appropriate antonym as it signifies the opposite action of restoring order and organization to the bookshelves.