According to the FortiOS 7.6 Administration Guide and Security Fabric documentation, automation stitches are designed to automate responses to security and system events across the network. A core characteristic of these stitches is their flexibility in action execution; specifically, multiple actions can run in parallel (Statement C). While the system allows for sequential execution with configurable delays between actions, the default behavior or configuration option allows for simultaneous responses, such as sending an email notification while simultaneously triggering a webhook or quarantining a host.

Furthermore, triggers can involve external connectors (Statement D). While many triggers are local to the FortiGate (such as reboots or log events), the Security Fabric allows the FortiGate to monitor and react to events from external components like FortiAnalyzer, FortiSIEM, or FortiClient EMS. For example, a FortiAnalyzer event handler can act as the trigger for a stitch on the root FortiGate. Statement A is incorrect because actions can target external systems like AWS Lambda or Slack which are not internal Fabric devices. Statement B is incorrect because each automation stitch is typically defined by a single trigger, though that trigger itself can be broad (e.g., "Any Security Rating Notification").