Your client copies HTML from an external source and pastes into the default WYSIWYG Editor...

Drupal uses text formats and filters to control how HTML input is processed before being displayed. One of the available filters is “Correct faulty and chopped off HTML” , which is specifically designed to fix improperly formatted or broken HTML markup.

According to Drupal documentation, this filter ensures that HTML pasted into editors (like CKEditor) is automatically cleaned and corrected , such as closing unclosed tags, fixing malformed markup, and preventing rendering issues. This is particularly useful when users paste HTML from external sources, which often includes inconsistent or invalid markup.

Option D is correct because it directly addresses the issue at the text format level without restricting allowed tags, maintaining the requirement to allow all HTML elements.

Option C is incorrect because enabling “Limit allowed HTML tags” would restrict HTML usage, which contradicts the requirement to allow all elements. Options A and B are not standard Drupal solutions and do not align with Drupal’s built-in filtering system.

Therefore, enabling the Correct faulty and chopped off HTML filter is the correct and recommended approach in Drupal 10 and Drupal 11.