Giventwocollectionobjectsreferencedbycol1andcol2,whichofthesestatementsaretrue?()

A.Theoperationcol1.retainAll（col2）willnotmodifythecol1object.

B.Theoperationcol1.removeAll（col2）willnotmodifythecol2object.

C.Theoperationcol1.addAll（col2）willreturnanewcollectionobject，containingelementsfrombothcol1 andcol2.

D.Theoperationcol1.containsAll（Col2）willnotmodifythecol1object.