What purpose does the bill of rights serve

The Bill of Rights is the first 10 amendments to the United States Constitution. These amendments guarantee essential rights and civil liberties, such as the right to free speech and the right to bear arms, as well as reserving rights to the people and the states.

Explanation:

1st amendment: freedom of speech, religion, petition, press, and assembly

2nd: right to bear arms

3rd: quartering of soldiers

4th: search and seizure

i believe the correct answer is option b. most eastern european nations joined nato.

though i could be wrong, option d. the eastern european nations were granted complete independence, would be another choice.

hope this ! : )