error LNK2005 on static class variable

Hi again,

I am getting this linker error below and could not quite figure out why. It seems that the linker is saying I declared my static class variable OptionFactory EuropeanCall::MyFactory mutliple times. Perhaps it is the way I am declaring it inside VanillaOptions.h I am rather new to C++ so it is not obvious to me.

Thank you for any help!

Linking...
OptionFactory.obj : error LNK2005: "public: static class OptionFactory<class BaseOption,class EuropeanCall> EuropeanCall::MyFactory" ( MyFactory@EuropeanCall@@2V $OptionFactory@VBaseOption@@VEuropeanCall@@@@A) already defined in MCMain.obj
VanillaOptions.obj : error LNK2005: "public: static class OptionFactory<class BaseOption,class EuropeanCall> EuropeanCall::MyFactory" ( MyFactory@EuropeanCall@@2V $OptionFactory@VBaseOption@@VEuropeanCall@@@@A) already defined in MCMain.obj
InitializeOptionFactory.obj : error LNK2005: "public: static class OptionFactory<class BaseOption,class EuropeanCall> EuropeanCall::MyFactory" ( MyFactory@EuropeanCall@@2V $OptionFactory@VBaseOption@@VEuropeanCall@@@@A) already defined in MCMain.obj
C:\tmp\CPP\Calvin\MC_VS_2005\MC\Debug\MC.exe : fatal error LNK1169: one or more multiply defined symbols found

//OptionFactory.h
//Creates new option based on the choice user made from menu

#ifndef OPTIONFACTORY_
#define OPTIONFACTORY_

#include <string>

template <class OptionType>
class OptionFactoryTemplate
{
public:
OptionFactoryTemplate(){};
virtual ~OptionFactoryTemplate(){};
virtual OptionType* CreateOption()=0;
};

template <class OptionType, class NewOption>
class OptionFactory : public OptionFactoryTemplate<OptionType>
{
public:
OptionFactory(){};
virtual ~OptionFactory(){};
virtual OptionType* CreateOption();
};

#endif

//BaseOption.h
//Define attributes and functions of a base option

#ifndef BASEOPTION_
#define BASEOPTION_

#include <map>
#include <OptionFactory.h>

class BaseOption
{
private:
double Strike, Expiration, RiskFreeRate, Price, Delta, Gamma, Vega, Theta;
public:
BaseOption(); //Constructor
virtual ~BaseOption(){}; //Virtual destructor
typedef OptionFactoryTemplate<BaseOption> BaseOptionFactory; //Baseoption factory
};

//Declare the global static option factory map
static std::map<std::string, BaseOption::BaseOptionFactory *> OptionFactoryMap;

#endif

//VanillaOptions.h
//Define all vanilla options, defined as single asset, non-path dependent options
//Includes : European Call/Put, Digial Call/Put on a single underlying

#ifndef VANILLAOPTIONS_
#define VANILLAOPTIONS_

#include <BaseOption.h>
#include <OptionFactory.h>

class EuropeanCall : public BaseOption
{
private:
BaseAsset UAsset; //Underlying asset
public:
EuropeanCall();
~EuropeanCall(){};
static OptionFactory<BaseOption, EuropeanCall> MyFactory;
virtual BaseAsset GetUAsset() const;
};

OptionFactory<BaseOption, EuropeanCall> EuropeanCall::MyFactory;

#endif

//MCMain.cpp
#include <MonteCarlo.h>
#include <UserInterface.h>
#include <VanillaOptions.h>
#include <iostream>

void main()
{
UserInterface ui; //User interface object
std::string OptionChoice;

//Output user interface to pick option choice until user chooses to stop
do {
OptionChoice = ui.MenuPickOption();
} while (ui.AskKeepGoing());

}