What Is a Primary Difference Between the OECD and UN

What is a primary difference between the OECD and UN model tax treaties?

A) The model espoused by the UN assumes all countries are equals,whereas the OECD model does not.
B) The model treaty advocated by the UN grants more taxing rights to the host country than does the OECD model when income repatriation is out of developing countries.
C) The model treaty of the UN gives more taxing rights to well-developed countries than developing countries.
D) All of the above are differences between the OECD and UN models.