How do phrases such as "port bow" and "gauge-c***s" affect the passage?
A. They serve to answer questions that Twain knows the reader will have when faced with a passage on steamboats.
B. They add humor to the passage, highlighting Twain's understanding that such technical language will confuse the reader.
C. They create a second, symbolic level of meaning that suggests how much of what happens on the ship is merely for show.
D. They give the passage authenticity and highlight Twain's own expertise and knowledge of steamboats.