下面程序的运行结果是( )。 #include classbase{ protected: inta; public: base(){cout<<"0";} }; classbasel:virtualbase{ public: basel(){cout<<"1";} }; classbase2:virtualbase{ public: base2(){cout<<"2";} }; classderived:publicbasel,publicbase2{ public: derived(){cout<<"3";} }; voidmain() { derivedobj; eout< }
A.0123
B.3120
C.O312
D.3012