With no explanation, chose the best option from "A", "B", "C" or "D". Ill We AFFIRM the district court’s order dismissing plaintiffs’ claims. 1 . The plaintiff-appellants also purport to challenge the district court's denial of limited jurisdictional discovery. However, the argument in their opening brief contains no discussion of the discovery ruling apart from a few statements suggesting dissatisfaction with it. See Aplt. Br. at 8 (“The Trial Court erred in dismissing the case ... without permitting any discovery as to the true nature and identity of SCTC.”); id. at 16 (suggesting that the case could be remanded to the district court for further factual development). Plaintiffs have therefore waived this issue through their failure to adequately address it in their opening brief. Cf. United States v. Beckstead, 500 F.3d 1154, 1164-65 (10th Cir.2007) (<HOLDING>); Christian Heritage Acad. v. Okla. Secondary

A: holding that appellant waived issue by failing to raise it in opening brief
B: holding that arguments not raised in the opening brief are waived
C: holding that the failure to raise an issue in the opening brief waives the issue
D: holding issue waived when discussion of it in the opening brief was limited to two section headings a single sentence in the briefs summary and two phrases in arguments otherwise challenging a separate issue
D.