Question:  Index of Effluency is the top prize awarded in a series of endurance races that  holds the Guinness World Record for what?
Sentence (from "24 Hours of LeMons"): The 24 Hours of LeMons is a series of endurance races held on paved road race courses across the United States, Australia (since October 2015) and New Zealand (first event held September 2016).
Relevant evidence: Yes