The Supreme Court case McCulloch v. Maryland ensured that:

A. it remained unclear whether a state law could contradict a federal one.

B. states did not have the power to tax citizens or businesses within their states.

C. states could operate their own banks without interference from the federal government.

D. a state law could be declared illegal if it contradicted the Constitution.

The correct answer is D. The Supreme Court case McCulloch v. Maryland ensured that a state law could be declared illegal if it contradicted the Constitution.

Explanation:

McCulloch v. Maryland is a famous case of the US Supreme Court. Maryland had imposed taxes on branches of the US Second Bank in the state to try to stop it from operating. Although the state law that imposed it stated that it applied to all banks that were not licensed by the state, in fact only the branches of the second US bank were in compliance with the terms, so the law was considered to be created specifically for it. The court invoked the necessary and appropriate provisions of the Constitution to show that Congress had the power to pass laws regarding themes that were not explicitly named in the Constitutional text.

Thus, the Supreme Court stated that the Constitution granted Congress the implicit right to fulfill its constitutional rights and to form a fully functioning government.

It also said that the state government had no power to legislate to prevent the federal government from exercising constitutional rights.