May the Department of Energy continue to transport these nuclear materials through the city of Centerville?
Yes, because the Department of Energy is a federal agency engaged in a lawful federal function and, therefore, its activities may not be regulated by a local government without the consent of Congress. 
Yes, because the ordinance enacted by Centerville is invalid because it denies persons transporting such materials the equal protection of the laws. 
No, because the ordinance is rationally related to the public health and safety of Centerville residents. 
No, because the Tenth Amendment reserves to the states certain unenumerated sovereign powers. 