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The sound device that is emphasized in both of the passages is C. repetition.
In poetry, repetition helps create a rhythmic pattern as well as emphasize an idea. It can consist of repeating the same word or phrase, sometimes even whole lines. In the passages we are inserted here, we can notice the repetition of a several words and phrases:
By the shores of Gitche Gumee,
By the shining Big-Sea-Water,
Stood the wigwam of Nokomis,
Daughter of the Moon, Nokomis.
Dark behind it rose the forest,
Rose the black and gloomy pine-trees,
Rose the firs with cones upon them;
Bright before it beat the water,
Beat the clear and sunny water,
Beat the shining Big-Sea-Water.
(Henry Wadsworth Longfellow, "The Song of Hiawatha")
We rest.—A dream has power to poison sleep;
We rise.—One wandering thought pollutes the day;
We feel, conceive or reason, laugh or weep;
Embrace fond woe, or cast our cares away:
(Percy Shelley, "Mutability")
Hope this helps!
Have a great day!