In which situation can a foreign country sue the United States according to the Eleventh Amendment?

The correct choice highlights that a foreign country cannot sue the United States. This is rooted in the principles established by the Eleventh Amendment, which provides states with sovereign immunity, effectively preventing lawsuits against them by individuals or foreign entities in federal court without consent.

The intent of the Eleventh Amendment is to protect states from being sued by citizens of another state or by foreign nations. This aspect of sovereign immunity means that the federal government, like states, is also protected against lawsuits from foreign countries unless Congress has explicitly allowed such actions.

Understanding this helps clarify why the other choices don't hold. Special permission from Congress would imply that there are specific situations where a lawsuit might be permissible, which contradicts the concept of inherent sovereign immunity. References to mutual treaties and state courts suggest situations where jurisdiction and legal obligations might conflict with the established principles of sovereign immunity, which are not applicable under the framework set by the Eleventh Amendment.