Which of the following is NOT a component of COMSEC?

The correct answer is operational security because it is a broader concept that encompasses various measures taken to identify and protect sensitive information from adversaries. While operational security is crucial for military operations and includes practices such as risk assessment and information classification, it does not specifically fall under the category of Communication Security (COMSEC).

COMSEC primarily focuses on protecting the integrity and confidentiality of communications, which includes measures such as ensuring physical security of communication equipment, controlling access to cryptographic materials, securing transmission channels, and preventing unauthorized emissions of signals. Physical security, transmission security, and emission security directly pertain to the safeguarding of communication systems and their transmissions, making them essential components of COMSEC.