In the case of a State that exercises the option under section 1396a(f) of this title , any individual who—

(A) (i) qualifies for a benefit under subsection (a), or (ii) meets the requirements of paragraph (1); and

(B) was eligible for medical assistance under the State plan approved under subchapter XIX in the month immediately preceding the first month in which the individual qualified for a benefit under such subsection or met such requirements,

shall remain eligible for medical assistance under such plan for so long as the individual qualifies for a benefit under such subsection or meets such requirements.