Demand is necessary in this situation for the debtor to be in delay:

Demand is necessary in this situation for the debtor to be in delay:

• A. When the time is a controlling motive.
• B. When the obligor has rendered it beyond his power to perform.
• C. When the obligation has been fulfilled.
• D. When the debtor delivers a wrong thing on due date.

Answer: (D)

Demand is necessary here because delay (mora solvendi) arises only when the creditor has required proper performance and the debtor fails to provide it. If the debtor delivers something other than what was required, the obligation has not been fulfilled correctly, but default on the due date isn’t automatically triggered until the creditor demands the correct performance and the debtor still does not comply. In this situation, the wrong delivery makes the performance incomplete or improper, so the creditor must request the right item; only after that demand—and the debtor’s failure to supply the correct thing—does delay attach. The other scenarios don’t fit because a fixed due date can itself trigger delay when time expires, impossibility excuses performance, and fulfilling the obligation means there is no default.

Demand is necessary here because delay (mora solvendi) arises only when the creditor has required proper performance and the debtor fails to provide it. If the debtor delivers something other than what was required, the obligation has not been fulfilled correctly, but default on the due date isn’t automatically triggered until the creditor demands the correct performance and the debtor still does not comply. In this situation, the wrong delivery makes the performance incomplete or improper, so the creditor must request the right item; only after that demand—and the debtor’s failure to supply the correct thing—does delay attach. The other scenarios don’t fit because a fixed due date can itself trigger delay when time expires, impossibility excuses performance, and fulfilling the obligation means there is no default.