Final answer:
After a law is passed by Congress and signed by the President, regulations are issued to enforce it.
Step-by-step explanation:
After a law is passed by Congress and signed by the President, it does not become a constitutional amendment (option a). It is also not immediately enacted without further steps (option b). Implementation does not depend on states' approval (option c). The correct answer is d. Regulations are issued to enforce the law. Once a law is enacted, government agencies create regulations to provide detailed instructions on how to comply with and enforce the law. These regulations are necessary for the effective implementation of the law.