What type of report would indicate a total loss of one primary mission?

The correct report that indicates a total loss of one primary mission is categorized as a CAT IV CASREP. This classification is used when a unit is faced with significant operational challenges due to material or equipment failure, resulting in the complete inability to perform a specific primary mission. It highlights the severity of the situation by indicating that the mission capability is lost entirely, prompting immediate attention and resources to resolve the issue.

In contrast, the other categories represent varying degrees of mission impairment. For example, CAT I CASREP deals with urgent and critical issues impacting mission capability but may not result in a total loss, while CAT II and CAT III CASREPs reflect lesser degrees of impact on mission readiness. Therefore, when a complete operational capability is lost, the precise reporting under CAT IV is essential for proper management and resource allocation.