YouaremaintainingyourOLTPdatabaseinOracle10g.YouhavenotsetthewarninglevelandcriticallevelthresholdvaluesforspaceusageoftheDATA1tablespace.Whatwillbetheimpact?()

A.Nowarninglevelorcriticallevelalertwillbegenerated.

B.Awarninglevelalertwillneverbegenerated，butacriticallevelalertwillbegeneratedwhen97percentspaceoftheDATA1tablespaceisused.

C.Acriticallevelalertwillneverbegenerated，butawarninglevelalertwillbegeneratedwhen85percentspaceoftheDATA1tablespaceisused.

D.Awarninglevelalertwillbegeneratedat85percentspaceusageoftheDATA1tablespace，andacriticallevelalertisgeneratedat97percentspaceusageoftheDATA1tablespace.