The correct answer is B) spatial.
The type of organization pattern that is most clearly used in this excerpt of Mark Twain’s “Life in the Mississippi is spatial.
A spatial pattern of the organization serves to arrange the information on a text according to how things fit together in the space described in the text, or the relation of the things described in a physical location. When using spatial pattern, it helps the reader to create a mental image of the distribution of things in a determined space or location. In this case, Mark Twain is describing what he is observing in the river and its surroundings. Indeed Twain uses a colorful and vivid description of what he is observing in his trip.