Access for Rural Communities Act or the ARC Act This bill allows sole community hospitals and Medicare-dependent small rural hospitals to have the Centers for Medicare & Medicaid Services (CMS) recalculate certain payment adjustments that were initially determined by Medicare administrative contractors. Specifically, if a hospital received a volume decrease adjustment from an administrative contractor prior to FY2018, the hospital may elect to have the CMS recalculate the adjustment using methodology that took effect in FY2018, as specified. The bill's provisions do not apply to final determinations made by administrative contractors more than three years before the date of enactment of this bill.