The six principles of the United States Constitution are as follows:
- Limited government
- Popular sovereignty (rule by the people)
- Checks and balances (equalized power between entities to ensure said power is not concentrated in one place)
- Judicial review (review of constitutionality by the Supreme Court of legislative acts)
- Federalism (federal system of government)
- Separation of powers (makes the legislative, executive, and judicial branches separate branches)
The only principle of the US Constitution listed in the options is separation of powers - the answer is option A.