Return base class in C#

Question

How can i return data that is in base class form?

A aclass = new A();
B bclass = aclass.GetB();

does not work.

public class B
{
    protected string str1;
    protected string str2;
}

public class A:B
{
    public A()
    {
         base.str1 = "A";
         base.str2 = "B";
    }

    public B GetB()
    {
        return base;
    }
}

Answer 1

GetB() is completely unnecessary. B bclass = aclass; is sufficient as aclass is already a B.