有如下程序: #inCluDE<iostrEAm> using nAmEspACE stD; ClAss pArt puBliC: pArt(int x=0):vAl(x) Cout<<vAl; ~pArt()Cout<<vAl; privAtE: int vAl; ; ClAss wholE puBliC: wholE(int x ,int y, int z=0):p2(x),p1(y),vAl(z)Cout<<vAl; ~wholE()Cout<<vAl; privAtE: pArt p1,p2; int vAl; ; int mAin() wholE oBj(1,2,3); rEturn 0; 程序的输出结果是()。 A.123321 B.213312 C.213 D.123123