Question: In an ad hoc group call across one or more MCVideo systems, what is the primary method by which the participants list can be determined for the call setup, reflecting a collaborative approach between user input and system policies?
Option 1: Using a combination of the criteria provided by the initiator of the call and the MCVideo server's own criteria or local policies.
Option 2: Solely based on the MCVideo server's predefined configurations without user input.
Option 3: Exclusively from the participants list provided by an external emergency service interface.
Option 4: Randomly selected from all subscribers of the MCVideo service.
Explanation: This is correct because, in mission-critical communication scenarios like ad hoc group calls, determining participants based on a combination of user-provided criteria and server-side policies ensures both the relevance of the call's recipients and adherence to security and operational protocols.