Small, prolific mussels called zebra mussels were first introduced into the great lakes by a foreign cargo ship. they became a serious problem because they attached themselves to smooth, hard surfaces, and often clogged water intake pipes. congress determined that zebra mussels posed a great threat to the economic welfare of the great lakes region and passed a statute requiring all great lakes water intakes to be coated with a special chemical compound that repels zebra mussels. studies by biologists at a major state university showed that while the special chemical compound that the federal government has required was effective, it also was toxic to other aquatic life. the biologists recommended that great lakes intake pipes be coated with a less toxic and less expensive copper-based paint. on the basis of those studies and the recommendation, three great lakes states adopted laws permitting municipal water districts to coat their intake pipes with copper paint. can municipalities using copper-based paint on their intake pipes successfully be prosecuted for violating the federal law? a no, because the tenth amendment prevents congress from interfering with integral government functions. b no, because the municipalities are taking effective steps to combat zebra mussels in compliance with the spirit and purpose of the federal law. c yes, because congress is in a better position to regulate the entire great lakes region than the individual states. d yes, because congress may adopt laws regulating navigable waters.