Final answer:
The main argument of the essay is that a government's primary duty is to protect its citizens, which is stated in the third sentence. The function of safety is historically and philosophically seen as fundamental for a society's operation. The correct answer to the student's question is: c. the third sentence.
Step-by-step explanation:
The main argument of the argumentative essay about government presented in the introduction is that an effective system of government is primarily there to ensure the safety of the nation and its residents.
Analyzing the sentences provided, the third sentence states the main argument clearly: 'While other concerns such as economic growth are important, a government's primary duty is to keep its people safe.' This sentence encapsulates the central thesis that, despite other roles governments may have, their foremost responsibility is the protection of citizens. It aligns with historical and philosophical views, such as those of Hume, Locke, and Rousseau, that suggest the need for a social contract where citizens trade some liberties for protection and public goods.
The essay alludes to several reasons for governments' existence, which can include the maintenance of order, provision of public goods, and the promotion of general welfare. Protection, according to philosophers and the introductive argument, seems paramount because without the concern of defense or self-protection, individuals are able to live in security, suggesting that safety is a fundamental prerequisite for a functional society.
The correct answer to the student's question is: c. the third sentence.