Setting a type reference type to null doesn't affect copied type?

Question

Why does this produce \"0\" ?

object a = 0;
object b = a;
a = null;
Console.WriteLine(b.ToString()); // Produces \"0\"
Console.Read();

Does

Answer 1

Here's a description of what's going on:

object a = 0; // pointer a = 0xSomeA
object b = a; // pointer b = 0xSomeB
a = null; // nulling a, now 0x00; b still the same