Select the correct answer.
Which detail explicitly states why the characters had to change their mode of transportation?
OA. "We started for the Klondike in the fall rush of 1897."
OB. "We packed our outfit on our backs part way over."
OC. "Then we had to buy dogs in order to sled it the rest of the way."
OD. "We started too late to get over Chilcoot Pass before the freeze-up."