Ambiguous error in inherite class c++

Ambiguous error in inherite class c++

so i will give a small example of what is my problem,can someone help me
resolve this:
class A
{
virtual void show()=0;
};
class B:public virtual A
{
void show(){/*content inside*/}
};
class C:public virtual A
{
void show(){/*content inside*/}
};
class D:public B,public C
{
void show(){/*content inside*/}
};
can someone help me in this ambiguous problem,because i want to use the
function show() in all classes,and i didn't quite understand how to solve
this