Final answer:
There were 525 delegates at the last National FFA Convention. The correct answer is D.
Step-by-step explanation:
The number of delegates at the last National FFA Convention was 525. The National FFA Organization (formerly known as the Future Farmers of America) hosts an annual convention where delegates from across the United States come together to represent their state FFA associations, vote on key issues, and set the direction of the organization for the coming year. As the number of delegates can vary from year to year, the precise count for the most recent convention must be obtained from official FFA channels or the convention's records. The correct answer is D.