Which Federal Act regulates insurance practices related to the Interstate Commerce?

The McCarran-Ferguson Act is the correct answer because it specifically addresses the regulation of insurance practices and affirms the states' authority to regulate the insurance industry. Enacted in 1945, this act established that states have the primary responsibility for regulating insurance, acknowledging that federal legislation should not interfere with state laws unless Congress explicitly states otherwise. This is important as it allows insurance companies to operate under state regulations, even when they engage in interstate commerce.

While the other acts listed focus on different aspects of health care and financial services, they do not directly relate to the regulation of insurance practices in the context of interstate commerce. For instance, the Affordable Care Act primarily deals with health care coverage and reforms, the Gramm-Leach-Bliley Act focuses on financial services and privacy, and the Health Insurance Portability and Accountability Act is centered on protecting personal health information. Therefore, the McCarran-Ferguson Act stands out as the specific legislation governing insurance practices across state lines.