Bydatabase design conventions, theprimary key is usually placed in the first columnof a table to make it easy to identify and reference.

Example Usage:

sql

CREATE TABLE Employees (

EmpID INT PRIMARY KEY, -- First column (convention)

Name VARCHAR(50),

Salary DECIMAL(10,2)

);

EmpID is placed as the first columnfor clarity and quick access.

Why Other Options Are Incorrect:

Option A (In the table header) (Incorrect):Table headers onlydisplay column names, they do not contain values.

Option C (In the top row) (Incorrect):Thetop row contains data, not theprimary key definition.

Option D (In the last visible column) (Incorrect):While technically possible,placing a primary key at the endisuncommonin database design.

Thus, the correct answer isIn the first column, as this is the standard convention in relational databases.