We need to question whether the results of the regression in part (d) is revealing a causal relationship between concentration and airfares. In particular, we are concerned whether our estimation results on U. S. data are valid for other markets, such as Europe and Asia. Give one reason why the results would not be \externally valid" if applied to the airline industry in one of these other two regions.

Cooper sues company a in state court in south carolina, where he lives, for negligence alleging personal injury and property damage of $100,000 after a truck driven by an employee of company a rear-ended his pickup truck. company a is incorporated in delaware, has its headquarters in new york, but does a substantial amount of business in south carolina. claiming diversity of citizenship, company a seeks removal to federal district court, but cooper opposes the motion. which of the following is true regarding whether the case may be properly removed to federal district court? the amount in controversy satisfies diversity requirements; and if company a's nerve center is in a state other than south carolina, then the case may be properly removed to federal court.the amount in controversy satisfies diversity requirements; and because company a is incorporated and has its headquarters in a state other than south carolina, the case may be properly removed to federal court.because the amount in controversy satisfies diversity requirements and company a is incorporated in a state other than south carolina, the case may be properly removed to federal court regardless of where company a's headquarters, nerve center, or principal place of business is located.because the amount in controversy satisfies diversity requirements and company a is headquartered in a state other than south carolina, the case may be properly removed to federal court regardless of where company a is incorporated and regardless of the location of its nerve center.because the amount in controversy fails to satisfy jurisdictional requirements, regardless of the location of company a, the case may not be removed to federal court.