Answer: C. By showing the soundness of his argument through a number of analogies.
Step-by-step explanation: There are many kinds of rhetorical devices used in writing or speaking to convince the audience of an argument about a controversial topic. One of the most common is "logos" which is an appeal to the audience's logic. In the given passage from "Resistance to Civil Government" by Henry David Thoreau, we can see an example of the use of logos by showing the soundness of his argument through a number of analogies (like comparing the mass of men with machines).