The correct option is C.
The supremacy clause states that the under the constitution of the United States of America, the federal laws are superior to state laws, therefore in time of conflict between the federal and the state law, the state law has to bow to federal law. Thus, the supremacy clause is used when federal and state laws are in conflict.
Music, he played a lot of Jazz
The Pentagon Papers "<span>were a secret study of the history of U.S. involvement in Vietnam," since their conclusions were highly controversial and the Johnson Administration initially blocked their release. </span>
Wagons were used to carry farmers wheat, cotton, and tobacco to markets.
You should read your history book and find the answer