The job of the police in keeping law and order in the society is

Services are classified as direct or indirect based on who benefits from them. A direct service benefits the specific individual who requests and pays for it, such as a doctor treating a private patient. An indirect service benefits the whole community or society generally, rather than one identifiable paying customer. The police keeping law and order protect everyone in society collectively, not a single paying client, which is why this is an indirect service.

The other options do not fit this situation. A self-service is one a person performs for themselves, such as cooking their own meal, which does not describe the police's role. A commercial service is one provided for profit in a business transaction between a specific provider and a paying customer, but policing is a public function funded by the state for the benefit of the whole society, not a profit-making commercial exchange.

Examination reminder: to tell direct and indirect services apart, ask who directly benefits: one identifiable person (direct) or society as a whole (indirect).