Which of the following attributes can be a primary key in the Task table?

You work as a Database Designer for Hitech Inc. You are designing a database named Project. The
company takes projects from outside and divides them into tasks (design, coding, etc.). Each task is
assigned to only one employee. You want to use a primary key constraint to uniquely define each
row in a table named Task. The tables are given below:

Which of the following attributes can be a primary key in the Task table?

A.
TaskID

B.
ProjectID

C.
EmployeeID

D.
SocialSecurityNumber (SSN)

Explanation:
The TaskID attribute uniquely defines each row in the Task table. It is given in the scenario that one
task is assigned to only one employee. Therefore, in order to avoid a task being given to two
employees, TaskID should be entered just once (unique).