14. The Affordable Care Act (ACA), also known as "Obamacare," introduced several key changes to the U.S. healthcare system. Choose the right provision(s) included in the ACA. (A) It required employers to provide free health insurance to all employees. (B) It mandated that insurance companies cannot deny coverage based on pre-existing conditions. (C) It required all Americans to purchase health insurance or face a financial penalty. (D) It allowed health insurance companies to deny coverage to individuals with pre-existing conditions.