What is the source reference that outlines SIRs?

The source reference that outlines SIRs, or Security Incident Reports, is indeed found in AR 190-45. This document is specifically focused on the policies and procedures related to security reports and incidents within the Army, making it the relevant resource for understanding the context, creation, and management of SIRs.

AR 190-45 covers how security incidents should be documented and reported, which is crucial for maintaining operational security and for responding to incidents efficiently. This regulation provides guidance on the types of incidents that need to be reported and the specific format to use, ensuring consistency and clarity across reports.

Other options, while containing relevant information on military regulations, do not focus directly on the specific procedures and guidelines for SIRs. For instance, AR 15-6 is primarily concerned with the procedures for investigations of misconduct, NGR 500-2 addresses national guard emergency management, and AR 20-1 deals with Army audits and inspections. Thus, the right choice emphasizes the importance of AR 190-45 specifically within the context of SIRs.