单选题 Given the following program:#include <iostream>using namespace std;class Base {private: void fun1( ) const { cout << "fun1"; }protected: void fun2 ( ) const { cout << "fun2"; }public: void fun3 ( ) const { cout << "fun3"; }};class Derived : protected Base {public: void fun4( ) const { cout << "fun4"; }};int main( ) { Derived obj; obj.fun1( ); // (1) obj.fun2( ); // (2) obj.fun3( ); // (3) obj.fun4( ); // (4) return 0;}Which lines followed with comment is not correct