Contributions to donor advised funds

A deduction otherwise allowed under subsection (a) for any contribution to a donor advised fund (as defined in section 4966(d)(2)) shall only be allowed if—

(A) the sponsoring organization (as defined in section 4966(d)(1)) with respect to such donor advised fund is not— (i) described in paragraph (3), (4), or (5) of subsection (c), or (ii) a type III supporting organization (as defined in section 4943(f)(5)(A)) which is not a functionally integrated type III supporting organization (as defined in section 4943(f)(5)(B)), and

(B) the taxpayer obtains a contemporaneous written acknowledgment (determined under rules similar to the rules of paragraph (8)(C)) from the sponsoring organization (as so defined) of such donor advised fund that such organization has exclusive legal control over the assets contributed.