; and (ii) at least one person described in subparagraph (B) is questioning or disputing the provision, withholding, or withdrawal of medical treatment, food, or fluids with respect to the beneficiary. (B) Interested Individuals A person described in this subparagraph, with respect to a beneficiary, is— (i) any individual who is a member of any class of persons who, under the applicable State’s law, would potentially be eligible to serve as a health care decision maker for the beneficiary if an advance directive had not been executed regardless of whether higher priority for such eligibility would be accorded to another individual or individuals; and (ii) if the applicable State’s law does not designate persons or classes of persons described in clause (i), any person related within the third degree of consanguinity or affinity to the beneficiary. (b) Registration (1) In general The Secretary shall establish procedures for an eligible beneficiary to register such beneficiary’s adoption of a certified advance directive under the Program. Such procedures shall ensure that registration is available through an online process. The Secretary shall also establish procedures to ensure Program participants can update previously registered information that is no longer accurate and indicate that an advance directive has been terminated. (2) Required information In addition to such other information as the Secretary may deem appropriate, an eligible beneficiary seeking to register a certified advance directive under the Program shall indicate where the advance directive is maintained or how it may be accessed. (3) Registration periods The procedures established under paragraph (1) shall provide that registration under the Program shall occur during— (A) an eligible beneficiary’s initial enrollment under an MA plan under part C as described in paragraph (1) of section 1851(e)