The State of A's constitution mandates that state judges retire upon reaching 70. Congress passes and the president signs legislation barring mandatory retirement ages for public and private employees in or affecting interstate commerce. The state of A sues the federal government, claiming that the law is unconstitutional. What statement is true?
(a) The federal law prevails over the state constitution under the Supremacy Clause.
(b) The state constitutional provision trumps a mere federal statute.
(c) The federal law exceeds congress' commerce power
(d) The federal law violates structural limits on Congress' commerce power because it attempts to regulate states as states.