Answer: c. Direct democracy
Step-by-step explanation:
In a Direct democracy, the people who are eligible to vote on matters that need to be voted upon do it themselves without the help of an intermediary or representative.
This differs from the democracy that we usually see today where people would vote for a representative who would then go to Congress/ Parliament and vote on issues that need voting for the people they represent (Representative democracy).
The Native American tribes listed are therefore practising direct democracy.