(a) To the extent federal financial participation is available, the department shall exercise the option under Section 1902(e)(12) of the federal Social Security Act (42 U.S.C. Sec. 1396a(e)(12)) to extend continuous eligibility to children 19 years of age and younger. A child shall remain eligible pursuant to this subdivision from the date of a determination of eligibility for Medi-Cal benefits until the earlier of either:
(1) The end of a 12-month period following the eligibility determination.
(2) The date the individual exceeds the age of 19 years.
(b) This section shall be implemented only if, and to the extent that, federal financial participation is available.
(c) Notwithstanding Chapter 3.5 (commencing with Section 11340) of Part 1 of Division 3 of Title 2 of the Government Code, the department shall, without taking regulatory action, implement this section by means of all county letters or similar instructions. Thereafter, the department shall adopt regulations in accordance with the requirements of Chapter 3.5 (commencing with Section 11340) of Part 1 of Division 3 of Title 2 of the Government Code.