题目内容（请给出正确答案）

[主观题]

You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty.Which statement accomplishes this task？（）

A. ALTER TABLE students ADD PRIMARY KEY student_id;

B. ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student _ id);

C. ALTER TABLE students ADD CONSTRAINT stud _ id _pk PRIMARY KEY (student _ id);

D. ALTER TABLE students MODIFY CONSTRAINT stud _ id _pk PRIMARY KEY (student _ id);

提问人：网友wk11766988 发布时间：2022-01-07

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