What action is inappropriate when handling classified information during transport?

Using clear text messages is inappropriate when handling classified information during transport because clear text communication does not offer any protection against unauthorized access or interception. When classified information is shared without encryption, it becomes vulnerable to adversaries or unauthorized personnel, compromising the confidentiality and integrity of that information.

In contrast, utilizing encrypted emails ensures that the contents are secure during transmission, following documented procedures is essential for maintaining accountability and compliance with regulations, and utilizing secure transportation methods protects classified materials from physical theft or exposure while in transit. Each of these actions supports the safeguarding of sensitive information, which is critical when transporting classified assets.