A junction object is a custom object that has two master-detail relationships with two other objects. A junction object allows administrators to create many-to-many relationships between objects, such as relating multiple accounts to multiple regions.
To create a junction object called Account Region to link the standard Account object with a custom object called Region, an administrator needs to do the following steps:
* A) Make a master-detail relationship field on the junction object to the Region object.
A master-detail relationship field is a field that links a child record to a parent record. The child record inherits the sharing and security settings of the parent record. By making a master-detail relationship field on the junction object to the Region object, an administrator can link each Account Region record to one Region record and make Region the first master of the junction object. References:
https://help.salesforce.com/s/articleView?id=sf.relationships_considerations.htm&type=5
* D) Configure a master-detail relationship field on the junction object to the Account object.
By configuring a master-detail relationship field on the junction object to the Account object, an administrator can link each Account Region record to one Account record and make Account the second master of the junction object. This allows administrators to relate multiple accounts to multiple regions through the junction object. References: https://help.salesforce.com/s/articleView?id=sf.relationships_considerations.htm&type=5