; and (B) an individual who has attained 18 years of age but has not attained 21 years of age, but only in the case of an individual— (i) who is in foster care under the responsibility of the State; (ii) with respect to whom an adoption assistance agreement is in effect under section 473 if the child had attained 16 years of age before the agreement became effective; or (iii) with respect to whom a kinship guardianship assistance agreement is in effect under section 473(d) if the child had attained 16 years of age before the agreement became effective. . (2) Conforming amendments Part E of title IV of the Social Security Act ( 42 U.S.C. 670 et seq.) is amended— (A) by amending section 473(a)(4)(A)(i) of such Act ( 42 U.S.C. 673(a)(4)(A)(i) ) to read as follows: (i) who has attained 21 years of age; ; (B) in section 471(a)(9)(C)(i)(I) of such Act ( 42 U.S.C. 671(a)(9)(C)(i)(I) ), by striking 18 years of age or such older age as the State has elected under section 475(8) of this Act and inserting 21 years of age ; (C) in section 472(c)(2) of such Act ( 42 U.S.C. 672(c)(2) ), by striking 18 and inserting 21 ; and (D) in section 475(5)(I) of such Act ( 42 U.S.C. 675(5)(I) ), by striking 18 years of age or such greater age as the State has elected under paragraph (8) and inserting 21 years of age . (b) Placement and interaction of siblings in foster care Section 471(a)(31) of the Social Security Act ( 42 U.S.C. 671(a)(31) ) is amended— (1) in the matter preceding subparagraph (A), by striking reasonable and inserting all available ; and (2) by striking subparagraph (B) and inserting the following: (B) in the case of siblings removed from their home who are not so jointly placed— (i) to place each such sibling at a distance that is in close proximity to the placement location of, and permits frequent, in-person contact with, all other siblings