关于以下C++代码，（ ）行代码会引起编译错误。
#include <iostream>using namespace std; class Base {private: int a;protected: int b;public: int c; Base() : a(1), b(2), c(3) {}}; class Derived : public Base {public: void show() { cout << a << endl; // Line 1 cout << b << endl; // Line 2 cout << c << endl; // Line 3 }};