The correct order of the sentences is: **b-a-c**.

So the completed text would read:

"We were excited about our annual school sports day. However, things didn't go exactly as planned. The events were well-organized, and everyone was ready to compete. During the relay race, one of the runners tripped and fell, which caused a delay. Despite the mishap, we managed to finish the races, and the day ended on a positive note."

The answer is **A. b-a-c**.