Which sentence best states the author's point in this excerpt?

A Dogsledding is an activity of the past that served early explorers well but is no longer necessary in the arctic.
B The Iditarod trail is approximately 1,000 miles whereas The Great Race of Mercy was closer to 1,500 miles.
C Dogsledding is a very challenging activity that requires the dogs and humans be in excellent condition.
D The Great Race of Mercy takes 8-11 days to complete and is run even if there are dangerous blizzard conditions.