ThedatabaseIsconfiguredinARCHIVELOGmode.Thedatabaseneedstobeup24X7.YouwanttoperformusermanagedbackupforthedatafilesoftheHR_DATAtablespace.Toaccomplishthetask，youissuedthefollowingcommand：SQL＞ALTERTABLESPACEhi_dataBEGINBACKUP；Whichtwostatementsaretrueinthisscenario？（）

A.Notransactiononthetablespaceisallowedbutyoucanperformqueries. B.Thetablespacewillautomaticallycomeoutofbackupmodewhenthefilecopyiscomplete. C.Thecheckpointchangenumberisfrozeninheadersofthedatafilesuntilthefileis removedfrombackupmode. D.Thedatabasewritesthebeforeimageofanentireblocktotheredostreambeforemodifying.blocktorthefirsttime.