Which of the following actions should be avoided when classifying information?

Using unmarked materials as a classification basis should be avoided because classification decisions must be made on clearly defined and properly marked sources to ensure appropriate handling and dissemination of sensitive information. Relying on unmarked materials carries a significant risk of misclassifying information, which could lead to unauthorized disclosure or mishandling.

Proper classification relies on established protocols and standards, where materials are explicitly marked to indicate their sensitivity and the reasons for their classification. This clarity helps to maintain information security and ensures that individuals correctly understand how to handle the information.

In contrast, delegating classification responsibilities, following established guidelines, and consulting with security personnel are all practices that support proper classification and enhance the security framework, making them acceptable actions in the classification process.