using namespace std; class B1{ int b1; public: B1(int i){ b1=i; cout<<b1; } ~B1( ){ cout<<"#1"; } }; class B2 { int b2; public: B2( ){b2=0; cout<<"*2"; } ~B2( ){ cout<<"#2"; } }; class C: virtual public B1,public B2 { int j; public: C(int a,int b,int c):B1(a),_______ ,j(c){cout<<"*3";} ~C( ){ cout<<"#3"; } private: B1 c1; B2 c2; };请为横线处选择合适的程序将派生类C的构造函数补充完整。