Which of the following issues is NOT addressed by tax treaties?

Question $1$ options:

a$)$

what tax disclosures must be made by a visitor to a host country

b$)$

treatment of business and investment income earned by a foreign visitor in the United States

c$)$

treatment of business and investment income earned by a foreign citizen in his home country

d$)$

how to compute the taxable amount in the host country

e$)$

all of these are correct