Which european philosopher believed that the purpose of government is to protect natural rights? a.john locke b.adam smith c.baron de montesquieu d.jean-jacques rousseau?

The answer is  John Locke. One of the most influential philosophers, the advocate of natural law, by which all humans are by nature the same, and against the claim that God subordinated all people to the monarch. So all men are equal before the law and the government, and they have the right to life, freedom and property, and the foundation of these rights is outside the law of any social organization. Locke was the advocate of a legitimate political government, as a kind of treaty between the government and people, in which people naturally could transfer some of their natural rights to the government, thus providing themselves with a stable and comfortable enjoyment in their lives, freedom and property. The government would thus promote the natural rights of people, guaranteed by law, and promote the public good, and people could always replace the government if it does not work in the public interest.