The correct option is Trigger.

A Trigger is the component that starts an automation and a scheduled notification requires a schedule to kick off the rule. For a weekly notification you must configure a Trigger that runs on the desired cadence so the automation can check for unresolved issues and then perform actions.

Smart values are used to read or format issue data inside actions and conditions and they do not start or schedule the automation, so they are not the required component here.

Condition is used to limit or filter which issues the rule acts on and it does not initiate the rule, so it is not the mandatory piece for a scheduled notification.

Send Slack message is an action that performs the actual notification and it is optional depending on how you want to notify the team, but the action by itself does not cause the automation to run on a schedule.

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