Which United States President addressed the National FFA Convention in 1978?

The correct answer is Jimmy Carter, who served as the 39th President of the United States. He addressed the National FFA Convention in 1978, marking an important moment for the organization as it showcased the government's support for agricultural education and leadership among youth. This event highlighted the significance of FFA and its role in promoting agriculture and developing leadership skills among students across the nation. Carter's focus on agriculture during his presidency and his recognition of the importance of rural communities made his address particularly relevant to the attendees at the convention. His engagement with FFA members helped reinforce the relationship between agriculture, education, and national policy.

The other options represent Presidents who did not address the National FFA Convention in that year; thus, they are less relevant to this specific question about the 1978 event.