Which of the following FFA events involves students competing with their knowledge of agricultural topics?

The event that involves students competing based on their knowledge of agricultural topics is the Career Development Event (CDE). These events are designed to enhance students’ skills and knowledge in specific areas of agriculture through competitions. In a CDE, participants apply what they have learned in their agriculture classes and FFA training in hands-on experiences and knowledge assessments related to various agricultural disciplines, such as agronomy, animal science, and food systems.

While other options may involve knowledge assessments or presentations, Career Development Events are specifically tailored to assess both the theoretical and practical aspects of students' knowledge in agriculture, making this choice the best fit for the question about competition focused on agricultural knowledge.