Which word best describes the author's tone in this excerpt from "That Spot" by Jack London? I don’t think much of Stephen Mackaye any more, though I used to swear by him. I know that in those days I loved him more than my own brother. If ever I meet Stephen Mackaye again, I shall not be responsible for my actions. It passes beyond me that a man with whom I shared food and blanket, and with whom I mushed over the Chilcoot Trail, should turn out the way he did. I always sized Steve up as a square man, a kindly comrade, without an iota of anything vindictive or malicious in his nature. I shall never trust my judgment in men again. Why, I nursed that man through typhoid fever; we starved together on the headwaters of the Stewart; and he saved my life on the Little Salmon. And now, after the years we were together, all I can say of Stephen Mackaye is that he is the meanest man I ever knew.

The narrator of this excerpt is sad, bitter, and sorry for having loved, trusted, and treated like a brother Stephen Mackaye. The narrator thought he knew Stephen Mackaye and believed he was an upright and kind man, but the narrator had a strong disappointment with this friend. This disappointment made him angry and spiteful and extremely sad. Therefore, as we read the excerpt, we notice an indignant tone in the narrative.