Which method is proper to transmit Confidential material to a military organization overseas with an APO/FPO address?

Transmitting Confidential material to a military organization overseas with an APO/FPO address requires adherence to strict protocol to ensure the security and integrity of the information. The U.S. Postal Service Registered Mail is the appropriate choice for this type of transmission because it provides a high level of security and tracking. This service is designated for sending valuable or sensitive items, and it includes features such as detailed record-keeping, a chain of custody, and insurance for the contents.

Using Registered Mail means that the sender receives a receipt, and each stage of the mail's journey is documented. This is crucial when dealing with Confidential materials, as it allows both the sender and the recipient to confirm that the material has been securely delivered and received.

While commercial air freight and overnight shipping services may offer rapid delivery, these methods do not necessarily provide the same level of security or tracking features as Registered Mail, making them less suitable for transmitting confidential materials. Standard Mail Class is not secure enough for this purpose, as it lacks the protective measures that are essential for sensitive information.