Which of the following best describes a social contract as defined by western philosophers in the 18th century?

Social Contract is defined as the rights and obligations of citizens to the government.  This can be seen through the laws that people must obey when they are in a country.  In the 18th century, the concept of social contract is that man surrenders some of his freedom in exchange for the benefits and protection that the state provides.  Some state that it rises from natural law where people obey the government in exchange for the protection of their rights.  Still if the conditions imposed on them is unfair, then they have right to challenge those conditions.