單項選擇題

您要對EMPLOYEES表的FIRST_NAME和LAST_NAME列創(chuàng)建一個組合索引。以下哪條語句將完成此任務(wù)()

A.CREATE INDEXfl_idx ON employees(first_name last_name)
B.CREATE INDEXfl_idx ON employees(first_name),employees(last_name)
C.CREATE INDEXfl_idx ON employees(first_name,last_name)
D.CREATE INDEXfl_idx ON employees(first_name);CREATE INDEXfl_idx ON employees(last_name)

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