Final answer:
The contract between Carlos and Danesh is frustrated due to the grounded flights of the airline. Both parties are relieved from their contractual obligations, and a new contract must be negotiated.
Step-by-step explanation:
In this case, the contract between Carlos and Danesh has been frustrated due to the unforeseen event of the airline's grounded flights. Frustration of a contract occurs when an unexpected event makes it impossible to fulfill the contract's obligations.
As a result of the frustrated contract, both parties are relieved from their contractual obligations. This means that Carlos is not responsible for the extra costs incurred in finding an alternative transport method, and Danesh cannot sue Carlos for breach of contract. Answer: c. The contract is frustrated, and a new one must be negotiated