Why must Washington’s tribes raise revenue?

to maintain their armed forces
to pay tribute to Washington state
to fund the tribal governments
to pay for food for their people

I think it is To fund the tribal governments.

Explanation:

It helps pay for housing, health care, public safety, environmental/natural resource programs and transportation. As tribal gaming money flows through the Washington economy, it generates hundreds of millions of dollars in tax revenues for local and state government.

macon. i believe thats the answer

sorry if im wrong.