To represent that an applicant has applied for a job when each applicant can apply to multiple jobs:
Option B: Junction object between Applicant and Job
Implementation:
Create a custom object, e.g., JobApplication.
Add master-detail relationships to both Applicant and Job.
Reference:
"Use a junction object to model a many-to-many relationship between two objects."
- Salesforce Help: Many-to-Many Relationships
Why Other Options Are Incorrect:
Option A: A master-detail from Applicant to Job implies that each Applicant is associated with only one Job.
Option C: A formula field cannot represent a many-to-many relationship.
Option D: A lookup field from Applicant to Job represents a one-to-many relationship, not many-to-many.