Whichtwostatementsaboutthebackgroundprocessofthedatabasewriteraretrue()

A.ItispossibletohavemultipledatabasewritersinanOracleinstance.

B.Itwritesdirtybuffers，ifany，todatafileswheneveracheckpointoccurs.

C.Itwritesdirtybuffers，ifany，todatafileswheneveratransactioncommits.

D.Itwritesdirtybuffers，ifany，todatafilesbeforethelogwriter（LGWR）writes