In which country is most of the Namib Desert located?

What is the highest mountain in Slovenia? What is the highest mountain in Bulgaria? What is the highest mountain in Romania? What is the highest mountain in Iceland? In which country is most of the Negev Desert located? In which country is most of the Simpson Desert located? In which country is most of the Rub' al Khali (Empty Quarter) located? In which country is most of the Thar Desert located?