What concept is used to derivatively classify the statement in the new document?

The concept of "Contained in" is applicable because derivative classification involves taking existing classified information and incorporating it into a new document. When you derive new documents from classified information, you must consider the classification of the original source material. By stating that the new document is "contained in" the existing classified information, it emphasizes that the underlying classification status remains intact and applicable to the new document. This method ensures that the new document properly reflects the classification levels of the information it includes, maintaining the necessary level of protection for sensitive data.