Final answer:
The sentence that is an example of direct characterization is when the author directly describes Simon Wheeler's appearance and traits.
Step-by-step explanation:
The sentence in this excerpt from Mark Twain's short story "The Celebrated Jumping Frog of Calaveras County" that is an example of direct characterization is:
"I found Simon Wheeler dozing comfortably by the bar-room stove of the dilapidated tavern in the mining camp of Angel's, and noticed that he was fat and bald-headed, and had an expression of winning gentleness and simplicity upon his tranquil countenance."
Direct characterization is when the author directly describes a character's appearance, personality, or traits. In this sentence, Twain directly describes Simon Wheeler as being fat, bald-headed, and having a gentle and simple expression on his face.