Declaring different type of object via macro

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C++

I need to handle below scenario.

class A()
{
   int i;
};

class B()
{
   int j;
};

class C
{
   int k;
};

class D
{
  int l;
}

class E:A
{
  MYMACRO obj
};

If class E is derived from class A, MYMACRO macro should create object of type C whereas if class E derived from class B MYMACRO macro should create object of type D.

How to achieve this via macro?

My requirement is I should not mention the type of object while declaring.The macro should check whether the current class is derived from this or that.Then it has to create the object of different types.

If there is any other solution apart from using macro please suggest me?

What I have tried:

I explored on it but Could not get solution for my scenario.