With no explanation, chose the best option from "A", "B", "C" or "D". Cir. 1988)); Aplee. Br. 21 (“[Elliott] asks this court to take the extraordinary step of exercising its supervisory power[ ] to suppress his statements.... ”). We recently emphasized our “circumspect approach to the exercise of the supervisory power.” United States v. Lilly, 810 F.3d 1205, 1219 (10th Cir. 2016); see also United States v. Payner, 447 U.S. 727, 734-35, 100 S.Ct. 2439, 65 L.Ed.2d 468 (1980) (noting Court’s “restrained application of the supervisory power,” which Court “applie[s] with some caution”). We don’t take lightly the assertion that a prosecutor has violated his ethical duties, and suppressing evidence is a stiff penalty. Thus, we typically demand full development of these issues in the district court. Cf. United States v. Thomas, 474 F.2d 110, 112 (10th Cir. 1973) (<HOLDING>). We lack the benefit of that development here.

A: holding that a trial courts determination of sanctions is committed to the trial courts dis cretion
B: holding that where both the appellate and trial courts are reviewing the paper record  there is no reason for the appellate courts to defer to the trial courts finding
C: holding that the problem is initially one for the trial courts
D: holding that the supreme courts proper scope of review of a trial courts decision in a trial de novo of an assessment matter is whether the decision of the trial court was clearly erroneous
C.