Paul and Daniel entered into a contract in writing on November 1, the essential part of which read as follows: "Paul to supply Daniel with 200 personalized Christmas cards bearing a photograph of Daniel and his family on or before December 15, 1970, and Daniel to pay $100 30 days thereafter. Photograph to be taken by Paul at Daniel's house. Cards guaranteed to be fully satisfactory and on time." Because Daniel suddenly became ill, Paul was unable to take the necessary photograph of Daniel and his family until the first week of December. The final week's delay was caused by Paul's not being notified promptly by Daniel of his recovery. Before taking the photograph of Daniel and his family, Paul advised Daniel that he was likely to be delayed a day or two beyond December 15 in making delivery because of the time required to process the photograph and cards. Daniel told Paul to take the photograph anyway. The cards were finally delivered by Paul to Daniel on December 17, Paul having diligently worked on them in the interim. Although the cards pleased the rest of the family, Daniel refused to accept them because, as he said, squinting at one of the cards at arm's length without bothering to put on his reading glasses, "The photograph makes me look too old. Besides, the cards weren't delivered on time.""Which of the following statements regarding the legal effect of Daniel's illness is LEAST accurate?
Daniel's illness and the related development excused Paul from his obligations to deliver the cards on or before December 15. Prompt notice by Daniel to Paul of Daniel's recovery from illness was an implied condition of Paul's duty under the circumstances. Paul was under a duty of immediate performance of his promise to deliver the cards on or before December 15 by reason of the express language of the contract and despite the illness of Daniel and the related developments. Daniel's conduct after his illness constituted a waiver of the necessity of Paul's performing on or before December 15.