Final answer:
The provision on a Medicare supplement policy's first page about the insurer's ability to change premium amounts is the Premium Provision.
Step-by-step explanation:
The provision that must be included on the first page of a Medicare supplement policy, which states the insurer's right to change premium amounts, is c) Premium Provision. This is because the premium provision outlines the terms regarding the payment processes, including how much the policyholder will pay and under what circumstances the insurer has the right to change these premium amounts. Insurance companies are required to provide this information to ensure policyholders are fully informed about the financial aspects of their coverage.