Which best describes a major impact of the U. S. Constitution?

Question 5 options:

A. It proclaimed the United States as a country independent from Great Britain.

B. It established the world's first republican government.

C. It established a government based on a document reflecting the will of the people.

It is not A) - this statement would rather describe the Declaration of Independence, another document.

It's also not B) - there were other republics before the US (including ancient Rome) and it also did not establish a Republican Government in the sense of the modern political party

So the correct answer is C!