With no explanation, chose the best option from "A", "B", "C" or "D". in turn. A. Retroactivity Plaintiffs first contend that application of the 2005 Rule to the wage indices for FFYs 2007 and 2008 constitutes impermissible, retroactive rulemaking. Dkt. 21-1 at 21. As an initial matter, the Secretary responds that Plaintiffs waived any retro-activity challenge to the rule by failing to raise that objection during the notice-and-comment period. Dkt. 23 at 21. “It is well established that issues not raised in comments before the agency are waived .... ” Nat’l Wildlife Fed’n v. EPA, 286 F.3d 554, 562 (D.C.Cir.2002), and Plaintiffs do not dispute that neither they nor any other party raised the retroactivity issue during the notice-and-comment period, see Dkt. 24 at 8-13; see also Dkt. 23 at 22; Burnett v. Sharma, 511 F.Supp.2d 136, 145-46 (D.D.C.2007) (<HOLDING>). Plaintiffs contend, however, that the Court

A: holding that where one argument is dispositive of the appeal we need not address the defendants other arguments
B: holding that the defendant waived any argument on the issue by failing to oppose a motion to dismiss
C: holding that party waived argument by failing to brief it on appeal
D: holding that plaintiff conceded argument raised in dispositive motion by failing to address it
D.