Which of the following is a step in establishing communications security (COMSEC)?

Establishing communications security (COMSEC) involves measures designed to protect sensitive information from unauthorized access and ensure secure communication channels. Implementing countermeasures to vulnerabilities is a crucial step in this process, as it directly addresses potential weaknesses that could be exploited by adversaries. By identifying and mitigating these vulnerabilities through various technical and operational measures, the overall integrity and confidentiality of communications are preserved.

Countermeasures can include encryption of communications, employing secure communication systems, and regular assessments of communication methods to identify areas for improvement. By implementing such measures, the risk of interception and compromise is significantly reduced, ensuring that all communications remain secure and reliable.

The other options do not align with the primary goal of enhancing communications security. While public relations campaigns, soldier morale initiatives, and inventorying equipment may contribute to overall military effectiveness, they do not specifically address the security risks associated with communications or the safeguarding of sensitive information. Therefore, focusing on countermeasures is essential to establish a robust COMSEC framework.