What Will Happen If You Try to Use the INSERT

Multiple Choice

What will happen if you try to use the INSERT command to insert a NULL value into a column that has been assigned a PRIMARY KEY constraint? ​

A) ​The command will execute because a PRIMARY KEY value can be NULL.
B) ​An error message is returned and the row is not added to the table.
C) ​The command will execute because only a UNIQUE constraint forbids NULL values.
D) ​An error message is returned but the unaffected portion of the row is added to the table.