Alberto Corelli offers to pay $2,500 to purchase a painting titled Moonrise from Tara Shelley, an artist whose works have been causing a stir in the art world. Shelley accepts Corelli's offer. Assuming that the contract has met all of the requirements for a valid contract, answer the following questions.

Both parties are adults, and the contract is in writing. The contract calls for Shelley to deliver the painting to Corelli's gallery in two weeks. Corelli has already arranged to sell the painting to a third party for $4,000 (a $1,500 profit), but it must be available for the third party in two weeks, or the sale will not go through. Shelley knows this but does not deliver the painting at the time promised. Corelli sues Shelley for $1,500 in damages. Shelley claims that performance was impossible because her mother fell seriously ill and required Shelley's care. Who will win this lawsuit, and why?