Final answer:
In Master-Detail relationships for custom objects, sharing settings are inherited from the parent object, and a specialized lookup field is required on the child object to establish the relationship. When the parent record is deleted, the child records are automatically deleted; both parent and child fields can be used for reporting.
Step-by-step explanation:
Regarding the Master-Detail relationships in custom objects within the context of a CRM system like Salesforce, let's analyze the given options:
- Sharing is inherited from parent: This is true, as in a Master-Detail relationship, the sharing and security settings of the child records are controlled by the parent record.
- Child needs to be manually deleted when the parent is deleted: This is false. In a Master-Detail relationship, when the parent record is deleted, the child records are automatically deleted as well.
- Only child fields are available for reporting: This is false. Both the parent and child object fields can be used for reporting purposes in a Master-Detail relationship.
- Lookup field is required on the child object: This is true, but more specifically, it is a special type of lookup field that creates the Master-Detail relationship.
Therefore, options 1 and 4 are true about Master-Detail relationships in custom objects, with a small clarification needed for option 4 that the lookup field is a specific type that establishes the relationship.