Answer:
first off it should be john es de mexico..not mexicano because thats saying what ethniticity he is.but anythewho the answer is El perro es de mexico.
Explanation:
i guess it depends on if this is based an article you had to read if not then you can say the dog is from anywhere.
1)Su
2)Sus
3)Vuestros
4)Nuestros
5)Sus
6) Nuestros