answer b is wrong.

In NFiB v Sebelius, Chief Justice Roberts held in his majority opinion that: a. the Affordable Care Act was unconstitutional bocause Congress did not have any authority to enact it. b. the Affordable Care Act was constitutional because Congress has the authonty to regulate commerce and the individual mandate was a necessary and proper exercise of that authority. C. the individual mandate was constitutional because the penalty the Affordable Care Act imposed for not buying insurance was a tax that Congress had the authority to pass. d. the Affordable Care Act was unconstitutional because Congress' use of the term "penalty" in the statute literally precluded him from finding that monies paid by an uninsured person to the IRS were a tax