10.abstractpublicclassEmployee{11.protectedabstractdoublegetSalesAmount（）；12.publicdoublegetCommision（）{13.returngetSalesAmount（）*0.15；14.}15.}16.classSalesextendsEmployee{17.//insertmethodhere18.}Whichtwomethods，insertedindependentlyatline17，correctlycompletetheSalesclass？（）

A.doublegetSalesAmount（）{return1230.45；}

B.publicdoublegetSalesAmount（）{return1230.45；}

C.privatedoublegetSalesAmount（）{return1230.45；}

D.protecteddoublegetSalesAmount（）{return1230.45；}