Which of the following cannot be used with the keyword virtual?

#include<iostream.h> 
class CuriousTab
{
    int *p; 
    public:
    CuriousTab(int xx, char ch)
    {
        p  = new int(); 
        *p = xx + int(ch); 
        cout<< *p;
    }
    ~CuriousTab() 
    {
        delete p;
    }
};
int main()
{
    CuriousTab objCuriousTab(10, 'B'); 
    return 0;
}

#include<iostream.h> 
struct MyData
{
    public:
    int Addition(int a, int b = 10)
    {
        return (a *= b + 2);
    }
    float Addition(int a, float b);
};
int main()
{
    MyData data;
    cout<<data.Addition(1)<<" ";
    cout<<data.Addition(3, 4);
    return 0; 
}

1. All operators can be overloaded in C++.
2. We can change the basic meaning of an operator in C++.

#include<iostream.h> 
class CuriousTab
{
    int x; 
    public:
        CuriousTab()
        {
           x = 0;
        }
        CuriousTab(int xx)
        {
            x = xx; 
        }
        CuriousTab(CuriousTab &objB)
        {
            x = objB.x; 
        }
        void Display()
        {
            cout<< x << " ";
        }
};
int main()
{
    CuriousTab objA(25);
    CuriousTab objB(objA);
    CuriousTab objC = objA;
    objA.Display();
    objB.Display();
    objC.Display();
    return 0; 
}