【单选题】
Examine the data in the EMPLOYEES table.<br /> EMPLOYEES<br /> EMP_NAME DEPT_ID MGR_ID JOB_ID SALARY<br /> EMPLOYEE_ID<br /> 101 Smith 20 120 SA_REP 4000<br /> 102 Martin 10 105 CLERK 2500<br /> 103 Chris 20 120 IT_ADMIN 4200<br /> 104 John 30 108 HR_CLERK 2500<br /> 105 Diana 30 108 IT_ADMIN 5000<br /> 106 Smith 40 110 AD.ASST 3000<br /> 108 Jennifer 30 110 HR_DIR 6500<br /> 110 Bob 40 EK_DIR 8000<br /> 120 Revi 20 110 SA_DIR 6500<br /> On the EMPLOYEES table, EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID. The JOB_ID column is a NOT NULL column.<br /> Evaluate this DELETE statement:<br /> DELETE employee_id, salary, job_id<br /> FROM employees<br /> WHERE dept_id = 90;<br /> Why does the DELETE statement fail when you execute it?（）
A、There is no row with dept_id 90 in the EMPLOYEES table.
B、You cannot delete the JOB_ID column because it is a NOT NULL column.
C、You cannot specify column names in the DELETE clause of the DELETE statement.
D、You cannot delete the EMPLOYEE_ID column because it is the primary key of the table.
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