Answer:
The correct answer is: commercial impracticability.
Step-by-step explanation:
Commercial impracticability is contained in US law, and that is considered as an excuse for contract compliance. This defense is provided in Article Second, Section 615 of the United States Uniform Commercial Code. The rule excuses the debtor from complying with his obligations «(...) if his execution in the agreed manner would be impracticable due to the occurrence of a contingency whose non-occurrence was a basic budget on which the contract was concluded or for the fulfillment of in good faith of any applicable foreign or domestic government regulation or order it is proved or not subsequently that it was invalidated ». The contingency must be unpredictable, the risk must not have been assumed directly or indirectly by the party requesting that its non-compliance be excused, which should not have caused the change of circumstances.