What is one result of the supremacy clause?

The correct answer is A. As a result of the Supremacy Clause, the Supreme Court can declare a state law unconstitutional.

Explanation:

The Second Clause of Article VI of the Constitution of the United States, more commonly referred to as the Supremacy Clause, states that the US Constitution, as well as the laws and treaties adopted by the federal government, constitute the supreme law of the nation. This means that the States of the United States are not sovereign and, as a last resort, it is always the authority of the Union that overrides the constitution and laws of each State of the Union. Therefore, if a state law is against any statement of the Constitution, the Supreme Court could declare it unconstitutional through the proceeding of Judicial Review.

im pretty sure it has something to do with the end of ww1

it foreshadows the theme of the paragraph and hints the topic that will be discussed in the paragraph!