Answer:
D) the supremacy of federal over state law
Explanation:
The Supremacy Clause of the Constitution of the United States (Article VI, Clause 2), establishes that the Constitution, federal laws made pursuant to it, and treaties made under its authority, constitute the "supreme Law of the Land", and thus take priority over any conflicting state laws.
Answer:
I guess you could say "120 people were interviewed in three social classes by me"