"To maintain grandfather status, the plan must include a statement that it is believed to be a grandfathered plan, and contact information for questions or complaints, in any summary of benefits provided to participants ... Self-funded or other group health plans that are not required to cover essential health benefits (EHB) but which cannot impose annual or lifetime dollar limits on EHBs that are covered can choose between the 51 EHB base-benchmark plans selected by a State or the District of Columbia and the FEHBP base benchmark plan."