Question: The 2010–11 Tour de Ski was the 5th edition of the Tour de Ski and took place from 31 December 2010 to which date, Swiss cross-country skier, Dario Cologna won the Men's class?
Sentence (from "2009–10 Tour de Ski"): The defending champions are Switzerland's Dario Cologna for the men and Finland's Virpi Kuitunen.
Relevant evidence: No