Final answer:
The term for people collectively establishing a government and mutual protection is the 'social contract', a philosophical concept where individuals consent to some restrictions for state-provided benefits and protections. Hence, option (d) is correct.
Step-by-step explanation:
The concept of people working together to create a government and protect each other is known as the social contract. The social contract is not an actual contract but a philosophical idea suggesting that individuals consent to surrender some personal freedoms in exchange for the protection and organization provided by a collective governance.
This idea was explored by thinkers like Thomas Hobbes, John Locke, and Jean-Jacques Rousseau, each putting forward a slightly different version, but all agreeing on the fundamental principle of a reciprocal relationship between the state and its citizens. Governments are empowered and limited by this social contract to provide public goods and services, such as national defense and public roads, as well as to protect the natural rights of the people.