In IBM QRadar SIEM, the Domain Management feature is designed to segregate data, typically for multi-tenant or segmented network environments. This segregation is achieved by assigning specific data-generating assets to a defined domain. The primary sources of data that QRadar processes are events and flows. Therefore, log sources, which generate event data, and flow collectors, which process and generate flow data, are the fundamental objects that can be assigned to a domain to ensure that all data they produce is tagged and isolated within that domain.

A. Users: Users are assigned to domains to control their data access permissions, but they are not a source of event or flow data.

B. Rules: Rules are logic constructs that operate on data within domains; they are not data sources that are assigned to a domain.

E. X-Force Integration Feed: The X-Force feed is a global source of threat intelligence data applied across the entire QRadar deployment, not a tenant-specific data source to be segregated by domain.

1. IBM QRadar SIEM Administration Guide (Version 7.5.0): In the section on "Domains," the guide explicitly lists the types of data that can be assigned to a domain. It states, "You can assign the following types of data to a domain: Log sources, Log source groups, Flow sources, Flow collectors, Scanners." This directly confirms that Log sources (D) and Flow collectors (C) are assignable. (IBM Security QRadar SIEM Administration Guide, Version 7.5.0, Chapter: "Domains", Section: "Domains").

2. IBM QRadar SIEM Core Functionality Guide (Version 7.5.0): This guide details the flow of data into QRadar. It describes how Event Collectors process logs from log sources and how QFlow Collectors process network packets into flow records. The Domain Management function then uses these defined sources as the basis for data segregation, reinforcing that log sources and flow collectors are the correct entities to assign to a domain. (IBM Security QRadar SIEM Core Functionality Guide, Version 7.5.0, Chapter: "QRadar SIEM components", Section: "Event and flow pipelines").