; specified alternative mechanisms (1) On-line information portal The Secretary shall establish an on-line portal which allows taxpayers to— (A) subject to such restrictions as the Secretary may provide, elect to begin or cease receiving payments under this section, and (B) provide information to the Secretary which is relevant in determining the monthly advance child payment and the taxpayer’s eligibility for such payment, including information regarding— (i) the number of the taxpayer’s specified children, including by reason of the birth of a child, (ii) the taxpayer’s marital status, (iii) the taxpayer’s modified adjusted gross income, (iv) the taxpayer’s principal place of abode, and (v) any other factor which the Secretary may provide. (2) Specified alternative mechanism For purposes of this section, the term specified alternative mechanism means the on-line portal established under paragraph (1), the on-line portal established under section 7527A, and any other mechanism or method established by the Secretary to allow taxpayer’s to provide the information described in paragraph (1) (including in connection with the filing of any return of tax). (3) Availability in multiple languages The Secretary shall ensure that the on-line portal described in paragraph (1) is available in multiple languages. (f) Specified child of more than 1 taxpayer (1) In general In the event that (without regard to this paragraph) a period of presumptive eligibility with respect to the same specified child would exist for more than 1 taxpayer at the same time— (A) except as otherwise provided in this section or by the Secretary, a period of presumptive eligibility shall exist only respect to the taxpayer with the most recent reference month, (B) the Secretary shall establish procedures under which the Secretary expeditiously adjudicates taxpayers’ competing claims of presumptive eligibility with respect to the same child, and (C) the Secretary shall notify any taxpayer of the termination of a period of presumptive eligibility