13. View the Exhibit that sets the threshold for the Current Open Cursors Count metric. Why is the Significance(意义) Level threshold type not available in the threshold setting?
A. because AWR baseline is not enabled
B. because Current Open Cursors Count is not a basic metric
C. because the STATISTICS_LEVEL parameter is set to BASIC
D. because the AWR baseline is a system-defined moving window baseline
知识点：
答案： B