Which of these details most clearly suggests that the figure Tom meets is the Devil? a He wears "a rude, half-Indian garb" and is sitting on a tree stump. b His eyes are read, and he is covered with soot. c His voice is hoarse and growling, and his hair is black. d He is powerfully built and is holding an ax.
I would say B, his eyes are red and he is covered with soot.
Because from what we know about the devil, he lives in a place where there's fire, and soot comes from fire. Also, he is often associated with the color red.