The EMPLOYEES table has these columns: LAST NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY ( SALARY DEFAULT 5000); What is true about your ALTER statement?（）

A. Column definitions cannot be altered to add DEFAULT values.
B. A change to the DEFAULT value affects only subsequent insertions to the table.
Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.
D. All the rows that have a NULL value for the SALARY column will be updated with the value 5000.