Which of the following is NOT a characteristic of a Primary Key in MySQL?

A Primary Key in MySQL is a special constraint used to uniquely identify each record in a table. It must contain unique values and cannot accept NULL values, as every row needs a definitive identifier. Therefore, Option B is the correct answer because it falsely claims that a Primary Key can accept NULL values. In reality, attempting to insert NULL into a Primary Key column will result in an error. Options A, C, and D are incorrect choices because they accurately describe Primary Key characteristics: uniqueness (A), the rule that a table can have only one Primary Key (C), and its role in uniquely identifying records (D). Understanding these constraints is essential for designing robust database schemas.