A manufacturer of widgets was incorporated in and has its principal place of business in State A. The manufacturer also operates its own stores in State A, State B, and State C, through which it sells its widgets to consumers. A consumer who resides in State D visited a State D store to purchase a widget. The State D store did not have the widget he needed, and employees at the store directed him to the State B store operated by the manufacturer. The consumer visited the manufacturerâs State B store and purchased the widget. The consumer returned to his home in State D, where he was injured while using the widget. The consumer intends to file a products liability action against the manufacturer in federal district court. In what district or districts is venue proper?