An HR system includes a Departments table and an Employees t…

An HR system includes a Departments table and an Employees table. Each employee record includes a field called DepartmentID that matches an entry in the Departments table. What role does DepartmentID play in the Employees table? Options:A. Primary KeyB. Candidate KeyC. Foreign KeyD. Surrogate Key Correct Answer: C. Foreign Key Explanation:DepartmentID links each employee to a department by referencing the Departments table. It is not unique in the Employees table, so it isn’t a primary or candidate key. Surrogate keys are artificial IDs, not cross-table references.

A subscription service keeps track of customers in a table c…

A subscription service keeps track of customers in a table called Customers. Each row has a unique CustomerID, along with fields like Name, Email, and JoinDate. Which field serves as the primary key in this table? Options:A. NameB. EmailC. CustomerIDD. JoinDate Correct Answer: C. CustomerID Explanation:The primary key must uniquely identify each record. Names and emails can be duplicated, and JoinDate certainly isn’t unique. CustomerID is specifically designed as a unique identifier.