Which one of these excerpts from Mark Twain's Life on the Mississippi best shows that the story is told by a subjective narrator?

A.
[The steamboat] has two tall, fancy-topped chimneys, with a gilded device of some kind swung between them.

B.
There was nothing generous about this fellow in his greatness.

C.
Four sons of the chief merchant, and two sons of the county judge, became pilots.

D.
Drays, carts, men, boys, all go hurrying from many quarters to a common center, the wharf.

B. There was nothing generous about this fellow in his greatness.

To determine which excerpt from Mark Twain's Life on the Mississippi best shows that the story is told by a subjective narrator, we need to understand what a subjective narrator means. A subjective narrator is one who includes their personal opinions, biases, or interpretations in the storytelling.

Let's examine each excerpt and see which one expresses a personal opinion or interpretation:

A. [The steamboat] has two tall, fancy-topped chimneys, with a gilded device of some kind swung between them.
This excerpt does not exhibit subjective narration as it simply provides a description of the steamboat's appearance without any personal opinion.

B. There was nothing generous about this fellow in his greatness.
This excerpt contains a personal opinion by saying that the person being described is not generous. It demonstrates a subjective viewpoint.

C. Four sons of the chief merchant, and two sons of the county judge, became pilots.
This excerpt does not showcase subjective narration as it solely provides factual information without any personal opinion or interpretation.

D. Drays, carts, men, boys, all go hurrying from many quarters to a common center, the wharf.
Similar to excerpt C, this sentence doesn't contain any subjective narration. It presents a factual observation without personal opinion or interpretation.

From these options, excerpt B - "There was nothing generous about this fellow in his greatness" - best demonstrates a subjective narrator as it involves a clear personal opinion about the person being described.

Therefore, the correct answer is B.