classClassA{publicintnumberOfinstances；protectedClassA（intnumberOfinstances）{this.numberOflnstances=numberOfinstances；}}publicclassExtendedAextendsClassA{privateExtendedA（intnumberOfinstances）{super（numberOflnstances）；}publicstaticvoidmain（String[]args）{E
题目
classClassA{publicintnumberOfinstances；protectedClassA（intnumberOfinstances）{this.numberOflnstances=numberOfinstances；}}publicclassExtendedAextendsClassA{privateExtendedA（intnumberOfinstances）{super（numberOflnstances）；}publicstaticvoidmain（String[]args）{ExtendedAext=newExtendedA（420）；System.out.print（ext.numberOflnstances）；}}Whichistrue？（）
A.420istheoutput.
B.Anexceptionisthrownatruntime.
C.Allconstructorsmustbedeclaredpublic.
D.ConstructorsCANNOTusetheprivatemodifier.
E.ConstructorsCANNOTusetheprotectedmodifier.