19. Which of the following statements best describes a novation? A. A novation occurs when the parties agree to mutually rescind their contract because of commercial frustration of purpose. B. A novation occurs when the parties agree to accept performance that is different from the performance originally promised because of commercial frustration of purpose. C. A novation occurs when the parties to a contract agree to substitute a third party for one of the original parties. D. Novations are illegal because they result from undue influence.