Which of the following statement is correct about the program given below?

#include<iostream.h> 
class Tab
{
    int x, y; 
    public:
    Tab(int x, int y)
    {
        this->x = x;
        this->y = y;
    }
    void Display()
    {
        cout<< x << " " << y;
    }
};
int main()
{
    int x = 50;
    int &y = x ;
    Tab b(y, x);
    return 0; 
}

#include<iostream.h> 
int main()
{
    int m = 2, n = 6;
    int &x = m++;
    int &y = n++;
    m = x++; 
    x = m++;
    n = y++;
    y = n++;
    cout<< m << " " << n; 
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 10;
    int &y = x;
    x = 25;
    y = 50;
    cout<< x << " " << --y;
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 0;
    int &y = x; y = 5; 
    while(x <= 5)
    {
        cout<< y++ << " ";
        x++;
    }
    cout<< x; 
    return 0; 
}

#include<iostream.h> 
class CuriousTabTest
{
    public:
    CuriousTabTest(int &x, int &y)
    {
        x++;
        y++;
    } 
};
int main()
{
    int a = 10, b = 20;
    CuriousTabTest objBT(a, b); 
    cout<< a << " " << b; 
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 10, y = 20;
    int *ptr = &x;
    int &ref = y;

    *ptr++;
     ref++;    

    cout<< x << " " << y;
    return 0; 
}

#include<iostream.h> 
class CuriousTabBase
{
    public:
    int x, y; 
    public:
    CuriousTabBase(int xx = 0, int yy = 0)
    {
        x = xx;
        y = yy; 
    } 
 };
class CuriousTabDerived : public CuriousTabBase
{
    private:
        CuriousTabBase objBase; 
    public:
    CuriousTabDerived(int xx, int yy) : CuriousTabBase(xx), objBase(yy)
    {
        cout << this->x   << " " 
             << this->y   << " "  
             << objBase.x << " "
             << objBase.y << " ";
    } 
    ~CuriousTabDerived()
    { }
};
int main()
{
    CuriousTabDerived objDev(11, 22); 
    return 0;
}

#include<iostream.h> 
class CuriousTab
{
    public:
    CuriousTab()
    {
        cout<< "Curious";
    }
    ~CuriousTab()
    {
        cout<< "Tab";
    }
};
int main()
{
    CuriousTab objTab;
    return 0; 
}

#include<iostream.h>
class CuriousTabBase
{   
    public:
    CuriousTabBase()
    {
        cout<< "Base OK. "; 
    }
    ~CuriousTabBase()
    {
        cout<< "Base DEL. "; 
    }
};
class CuriousTabDerived: public CuriousTabBase
{
    public:
    CuriousTabDerived()
    { 
        cout<< "Derived OK. "; 
    }
    ~CuriousTabDerived()
    { 
        cout<< "Derived DEL. "; 
    }
};
int main()
{
    CuriousTabBase *basePtr = new CuriousTabDerived();
    delete basePtr;
    return 0;
}

#include<iostream.h> 
class CuriousTab
{
    int x; 
    public:
    CuriousTab(int xx, float yy)
    {
        cout<< char(yy);
    } 
}; 
int main()
{
    CuriousTab *p = new CuriousTab(35, 99.50f);
    return 0; 
}

#include<iostream.h> 
int val = 0; 
class CuriousTab
{
    public: 
    CuriousTab()
    {
        cout<< ++val;
    }
    ~CuriousTab()
    {
        cout<< val--; 
    } 
}; 
int main()
{
    CuriousTab objCuriousTab1, objCuriousTab2, objCuriousTab3;
    {
        CuriousTab objCuriousTab4;
    } 
    return 0;
}