With no explanation, chose the best option from "A", "B", "C" or "D". procedures fell within the discretionary function exception and that its “judgment in deciding what tests were necessary to meet reasonable safety requirements ... require[s] a balancing of social and economic interests and a tailoring of safety requirements to local conditions.” In so holding, we noted that “ [determination of safety requirements involves a balancing of social, economic or political policies” and that “when Congress leaves the establishment and enforcement of safety standards to an agency, it intends an exercise of that discretion to fall within the discretionary function exception.” Id. at 1047-48 (citing Cunningham v. United States, 786 F.2d 1445, 1447 (9th Cir.1986)); accord Colorado Flying Academy, Inc. v. United States, 724 F.2d 871, 876-77 (10th Cir.1984) (<HOLDING>). Sidestepping these cases, Airlog argues that

A: recognizing a discretionary function exception to that waiver
B: holding that the constitution can limit the discretion of federal officials such that the ftcas discretionary function exception will not apply
C: holding that the discretionary function exception may apply in the absence of a conscious decision 
D: holding that terminal control area design was left to the discretion of the faa designer and that competing interests were weighed and then policy decisions were made which the discretionary function exception was intended to cover
D.