Pendidikan formal dan informal adalah usaha pengendalian sosial yang
a. represif c. coersive
b. preventif d. intimidasi

@b because you most likely want to pick the secondo one in multiple choice

An informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.