Read the following excerpt from a US court opinion:
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agreements because, the district court reasoned, the agreements violate the Assignment of Claims Act (hereinafter the Act), 31 U.S.C. § 3727, which governs the “transfer or assignment of any part of a claim against the United States Government,” id. § 3727(a)(1). This determination was in error. The Act provides, in relevant part, that the assignment of a claim may be made “after a claim is allowed, the amount of the claim is decided, and a warrant for payment of the claim has been issued.” Id. § 3727(b). In effect, the Act serves as a defense that the Government can raise against a claim and not, as the district court’s analysis indicates, an ex ante bar to forming a contingency-fee agreement. See, e.g., United States v. Transocean Air Lines, Inc., 386 F.2d 79, 82 (5th Cir.1968) ; see also Applegate v. United States, 35
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What is the most suitable continuation to the opinion? Your options are:
A. holding a violation of the travel act
B. holding retroactive application of the act to prosecution that was pending before the effective date of the act was precluded because the act is prospective
C. holding that 31 usc  235 the predecessor to  3729 did not become operative until final payment had been made on the false claims
D. holding that antiassignment provisions are not per se invalid as applied to health care providers
E. holding that counsels claim against the government pursuant to a contingencyfee agreement was invalid because it was in violation of the antiassignment act 31 usc  203 predecessor to the assignment of claims act
Reply with [A, B, C, D, E] only.