4. A singer and a producer signed a document, in which the singer agreed to perform at a city concert hall on February 15, 16, and 17, in return for 10% of the gross income from the sale of tickets. The city concert hall is owned by the producer and uninsured. On February 14, the concert hall was destroyed by a fire, through no fault of either the singer or the producer, after the singer had arrived in the city ready to perform. In a suit between the singer and the producer: A. The singer is entitled to nothing, because of the doctrine of frustration of purpose. B. The singer is entitled to nothing, because of the doctrine of impossibility of performance. C. The singer is entitled to recover expenses from the producer. D. The singer is entitled to $6,000, if $60,000 worth of tickets had been sold prior to February 15.