Read this excerpt from The Call of the Wild. Since the beginning of the winter they had travelled eighteen hundred miles, dragging sleds the whole weary distance; and eighteen hundred miles will tell upon life of the toughest. Buck stood it, keeping his mates up to their work and maintaining discipline, though he, too, was very tired. Billee cried and whimpered regularly in his sleep each night. Joe was sourer than ever, and Sol-leks was unapproachable, blind side or other side.

Which part of the excerpt is the best example of indirect characterization?

A. the description of Buck “maintaining discipline”
B. the statement that Buck is also “very tired”
C. the description of Joe as “sourer than ever”
D. the statement that Sol-leks is “unapproachable”