Answer:
confederal
Explanation:
Confederal organisation structure is a union of sovereign groups that come together for a common purpose. It is characterised by a weak central structure with the group's being independent.
Distribution of power among the group's is variable. Decisions made are as a.result of consensus between parties involved.
In the scenario the National Independent Automobile Dealers Association (NIADA) is made up of 50 largely independent state-level organizations.
They come together to provide membership benefits to car dealers.
The is a form of confederal organisation structure.