Which statement about comments in the expression editor is true?

The statement regarding comments in the expression editor that is accurate is the one that indicates a double forward slash (//) allows a comment to be added to the expression box. In many programming and scripting languages, including the syntax used in Alteryx's formula tools, a double forward slash is the standard way to denote that the rest of the line is a comment. This helps in making the code or expression more understandable to users by providing context or explanations without affecting the execution of the actual code.

The ability to add comments in this manner is essential for documentation purposes, as it allows users to annotate their logic, making collaboration easier and facilitating future modifications. By using double forward slashes, users can ensure that any text following this notation will not be interpreted as part of the formula or expression, thus preserving the integrity of their calculations.