Select the correct NATO portion marking for NATO CONFIDENTIAL information in a U.S. document.

The correct marking for NATO CONFIDENTIAL information in a U.S. document is indeed indicated as (//NATO NC). This marking is essential for proper classification and handling of sensitive information related to NATO, ensuring that personnel understand the level of confidentiality required for such data.

The use of the designation "NC" specifically denotes NATO CONFIDENTIAL status, which is one of several classification levels within NATO, including CONFIDENTIAL, SECRET, and TOP SECRET. By consistently applying the correct marking, organizations can maintain secure communication and protect classified material, thus adhering to both NATO standards and U.S. classification guidelines.

The accurate marking process reflects the importance of diligence in handling classified information, as it informs readers about the sensitivity of the material and the associated security protocols. Properly marking NATO CONFIDENTIAL information is crucial for safeguarding national security and alliance-related operations.