Which answer best defines classified cargo?

Classified cargo is best defined as items that are marked with specific classification levels such as CONFIDENTIAL or SECRET. This classification indicates that the information concerning the cargo is sensitive and that its disclosure could harm national security. Such items require special handling procedures, including signature service to verify receipt and ensure that only authorized individuals have access to them.

The other options, while related to certain aspects of cargo handling, do not capture the essence of classified cargo. For instance, cargo related to military exercises could include various types of materials, but not all of it would be classified. Similarly, cargo exceeding weight limits concerns regulations about transport capacity rather than the sensitivity or classification of the cargo itself. Monitoring by security personnel could apply to various types of cargo but does not specifically denote a classification status like CONFIDENTIAL or SECRET. These distinctions highlight the unique characteristics associated with classified cargo and why it is critical to follow proper protocols for its handling.