[单项选择]Oracle9i offers the ability to monitor the dynamic use of the SGA through the DB_CACHE_ADVICE parameter. When this parameter is set to READY, what is its effect? () A. The Advisory is on and will capture both CPU and memory overhead. B. The Advisory is on but the memory for the Advisory is not allocated. C. The Advisory is off and the memory for the Advisory is not allocated. D. The Advisory is off but the memory for the Advisory remains allocated.