The Secretary, to the extent he finds it to be cost-effective and efficient and not inconsistent with the purposes of this subchapter, may waive such requirements of section
1396a of this title (other than subsection (s)) (other than sections
1396a
(a)(15),
1396a
(bb), and
1396a
(a)(10)(A) of this title insofar as it requires provision of the care and services described in section
1396d
(a)(2)(C) of this title) as may be necessary for a State—