Questions: When federal law takes precedence over state law, this is called Presumption Presupposition Preemption Proposition

The answer is: Preemption.

Explanation for each option:

1. Presumption: This term generally refers to an assumption or belief that something is true without requiring proof. It is not related to the legal principle where federal law overrides state law.

2. Presupposition: This term refers to something assumed in advance or taken for granted. It is more commonly used in the context of logic and linguistics, not in the context of legal hierarchy.

3. Preemption: This is the correct term. In the context of U.S. law, preemption refers to the principle that federal law takes precedence over state law. This is based on the Supremacy Clause of the U.S. Constitution, which establishes that federal law is the "supreme Law of the Land."

4. Proposition: This term generally refers to a statement or assertion that expresses a judgment or opinion. It is not related to the legal principle where federal law overrides state law.

Therefore, the correct answer is Preemption.