A refrigeration-unit manufacturer contracts to sell 100 units to a store with delivery by March 30. A strike delays the shipper; the manufacturer delivers on April 18. The store sues for breach. Which fact provides the strongest defense for the manufacturer?

• A. The store waived the delivery-date requirement by accepting late delivery.
• B. The contract contains an express-delivery-delay clause.
• C. Parol evidence prohibits considering trade usage.
• D. Industry trade usage allows a 30-day leeway for delivery; April 18 is within that window.

Answer: (D)

The key idea is that terms in a contract for the sale of goods can be shaped by industry practices known as usage of trade. If the contract doesn’t spell out a fixed delivery window, a seller can defend a late delivery by showing that a recognized industry practice allows a reasonable extension.

Here, the refrigeration-unit market uses a 30-day leeway for delivery beyond the stated due date. The contract set the due date at March 30, but delivery on April 18 is within that 30-day window. Under usage of trade, this counts as timely performance, so the late delivery isn’t a breach. This defense rests on shared industry norms rather than a specific clause or the buyer’s acceptance actions.

Why the other options aren’t as strong: waiving the delivery date would require knowledge and acceptance of late delivery by the buyer, which isn’t stated; parol evidence doesn’t bar considering trade usage and would not override industry practice when interpreting terms; an express-delivery-delay clause could govern, but the prompt focuses on industry usage as the strongest basis for timely performance in this case.