Sen. Chuck Grassley has questions about what the feds are doing to investigate allegations of Medicare Advantage fraud. Drew Angerer/Getty Images hide caption

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Carol Berman, of West Palm Beach, Fla., makes the case for policymakers to protect Medicare Advantage benefits during the Coalition for Medicare Choices' Medicare Advantage Food Truck stop in Washington, D.C., on Monday. Bill Clark/CQ-Roll Call/Getty Images hide caption

itoggle caption Bill Clark/CQ-Roll Call/Getty Images