Changing the field type to a Lookup Relationship will allow deleting the Relationship field without deleting the Runners records. A lookup relationship creates a loose association between two objects, where the child records do not depend on the parent records for their existence. A lookup relationship can be deleted without affecting the child records, unlike a master-detail relationship that enforces cascading deletes. Reference: https://help.salesforce.com/s/articleView?id=sf.relationships_considerations.htm&type=5

Assignment rules and validation rules are two features that can satisfy these requirements:
Assignment rules are used to automatically assign leads or cases to users or queues based on certain criteria. In this case, an assignment rule can be used to assign leads to different planetary teams depending on which planet the lead is coming from.
Validation rules are used to validate the data entered by users and prevent records from being saved if they do not meet certain criteria. In this case, a validation rule can be used to ensure that every team has all of the information they need by making certain fields required or dependent on other fields.
The other two options are incorrect because:
Matching rules are used to identify duplicate records based on certain fields or fuzzy logic. They do not assign records or validate data.
Workflow rules are used to automate tasks or actions based on certain criteria. They do not assign records or validate data.

An after save flow is a type of flow that runs in the background after a record is saved and performs actions based on the record data or changes. An after save flow does not require user input or interaction and can be triggered by a record-triggered flow element or by an Apex trigger. In this case, you can create an after save flow that runs when a case record is updated and delivers status update email to customers based on certain criteria or conditions. Reference: https://help.salesforce.com/s/articleView?id=sf.flow_trigger_types.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.flow_concepts_trigger.htm&type=5

The user profile permissions on the Opportunity object is the item that the administrator should review to find out why the user is unable to delete the duplicate record. The user profile permissions determine what users can do with records and objects in Salesforce, such as creating, editing, deleting, viewing, or sharing. In this case, the administrator should check if the user has the Delete permission on the Opportunity object, which allows them to delete opportunity records that they own or have access to. If not, the administrator can either grant them this permission or delete the record for them. Reference: https://help.salesforce.com/s/articleView?id=sf.admin_general_permissions.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.admin_object_permissions.htm&type=5

A cross filter with WITHOUT logic is a method for creating a report that shows accounts that are missing certain related records. A cross filter is a filter that lets you include or exclude records in your report based on related objects and their fields. You can use cross filters to create reports on accounts with or without opportunities, contacts, cases, or other related objects. In this case, you can use a cross filter with WITHOUT logic to show accounts without assets that have a certain product name or code. This way, you can identify customers that need to install a new solar panel monitor system. Reference: https://help.salesforce.com/s/articleView?id=sf.reports_cross_filters.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.reports_examples_cross_filters.htm&type=5