Which best describes john c. calhoun’s views on states’ rights?
a state legislature can declare a law it believes to be unconstitutional as null and void within its borders.

only the u. s. supreme court can declare a federal law to be unconstitutional.

the federal government was created by the american people and therefore no state has the right to leave it.

each state should be free to conduct its own foreign policy without the interference of the federal government.

A is correct.

Explanation:

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation:

legislative branch:

one of the three branches of government divided between the senate and the house of representatives.

- creates or makes laws

- power to override a veto

executive branch:

one of the three branches of government, headed by the president.

- enforces or carries out laws

- power to veto a bill sent to it by congress

judicial branch:

one of the three branches of government, headed by the chief justice of the supreme court.

- interprets laws

- power to declare laws or actions by the government unconstitutional