Question: What platform was the Mercedes-Benz GLK's 2008 debut competitor based on?
Sentence (from "Mercedes-Benz GLK-Class"): The Mercedes-Benz GLK (codename X204) is a compact luxury crossover SUV that went on sale from the autumn of 2008 after its public debut at the 2008 Beijing Auto Show alongside the competing Audi Q5.
Relevant evidence: Yes