Washington State recently passed a law to de-criminalize the purchase and use of small amounts of marijuana for personal use within the State of Washington, for residents over 21. However, if a Washington business sets up a store to sell marijuana, they could still be prosecuted by the federal government. This is because in a conflict between state law and federal law, the federal law will prevail, due to which part of the US Constitution?

a.	Due Process Clauses c. Supremacy Clause
b.	Equal Protection Clause d. Federalism doctrine