Answer:
B) the US Constitution
Step-by-step explanation:
The US Constitution is the base of all US legal system, which means that all laws need to be valid according to the US Constitution. If any law conflicts with the Constitution it should be ruled unconstitutional by the US Supreme Court - which means that the law will not be valid anymore to all citizens - or by a single judge - which means that this law would not be applied to the single case anymore.