Answer: Impossibility
Explanation: Impossibility is the excuse term under the contract which describes about duties that cannot be completed by one or more parties under the normal conditions in accordance with contract law .This excuse usually arises due to the unavoidable circumstances such as injury of the participant, failure of the subject, destruction of the field etc.
The situation mentioned in the question also depicts about the impossibility. As Peter's car got burnt , so he cannot perform in the race as car is not operable in the situation.