extern confusing problem

[Wolvorine]

hi,
i have class A ,B and D.

A class header file has a variable with static scope. Inside C and B the same name variable is defined with extern scope. When i run these objects inside the main function it doesnt change the data of that variable accept class D.

here are the class A.h and .cpp

#pragma once

static int iTheBad;

class A
{
public:
	A(void);
	~A(void);
};


A::A(void)
{
	iTheBad=19;
}

A::~A(void)
{
}

here its class B

#include "A.h"
extern  int iTheBad;
#pragma once


class B
{
public:
	B(void);
	~B(void);
};



B::B(void)
{

	iTheBad=32;
}

B::~B(void)
{
}

here is the D class

#include "A.h"
extern  int iTheBad;

#pragma once

class D
{
public:
	D(void);
	~D(void);
};



D::D(void)
{
	iTheBad=1132;
}

D::~D(void)
{
}

here is the code, only D class changes the variable while B and A dont change anything ..... Thats really confusing why?????

#include "stdafx.h"
#include "A.h"
#include "D.h"
#include "B.h"


int _tmain(int argc, _TCHAR* argv[])
{
	extern int iTheBad;

//    iTheBad=0;

	A Obj1;
	D Obj3; //it works perfectly  and change the variable to 1132
	B Obj2;


	return 0;
}