Result of calling IEquatable.Equals(T obj) when this == null and obj == null?

Question

What should IEquatable.Equals(T obj) do when this == null and obj == null?

1) This code is generated

Answer 1

I would definitelly go with option 1:

    if (this == null)
    {
        return obj == null;
    }
    if (obj == null)
    {
        return false;
    }

null object always equals null object.