Final answer:
The correct data model for tracking the relationship between people and their employers, allowing for many-to-many relationships, is to create a junction object with master-detail relationships.
Step-by-step explanation:
The question is asking which data model should be used to track the relationship between people and their employers in an application enhancement. The appropriate data model to use in this scenario is A. Create a junction object to relate many people to many employers through master-detail relationships. This solution allows for the creation of a many-to-many relationship between people and employers, which is necessary if employees can work for multiple employers and employers can have multiple employees.
In Salesforce, a junction object is a custom object with two master-detail relationships, and it's the standard way to handle many-to-many relationships. A lookup relationship (B. Create a lookup relationship to indicate that a person has an employer) is used for one-to-many relationships, which does not fit the requirement if an employee can have multiple employers or vice versa. Option C mentions using lookup relationships in a junction object, which is inaccurate since a junction object by definition uses master-detail relationships. D. Create a master-detail relationship to indicate that a person has an employer also does not suffice as it represents a one-to-many model. Therefore, option A is the correct choice for this enhancement.