Read the following excerpt from Henry David Thoreau's "Resistance to Civil Government."

Action from principle, the perception and the performance of right, changes things and relations. . . . It not only divides States and churches, it divides families; ay, it divides the individual, separating the diabolical in him from the divine.
Which of these rhetorical devices does Thoreau most clearly use here?

A.
Metaphor

B.
Parallelism

C.
Ethos

D.
Rhetorical question

B. Parallelism

To determine which rhetorical device Thoreau most clearly uses in the given excerpt, we can analyze the text and understand the purpose of each device.

A metaphor is a figure of speech that compares two different things by stating that one thing is another. In the excerpt, Thoreau does not directly compare or equate any two things using figurative language, so it is not a metaphor.

Parallelism is the use of similar grammatical structures or constructions to create a pattern or rhythm within a sentence or paragraph. In the excerpt, Thoreau does not employ parallelism in terms of repeating similar grammatical structures, so it is not parallelism.

Ethos is an appeal to ethics or credibility used to persuade an audience. In the excerpt, Thoreau does not employ any specific ethical appeals to gain credibility or convince the readers of his arguments, so it is not ethos.

A rhetorical question is a question posed for dramatic effect or to emphasize a point rather than to elicit a direct answer. In the excerpt, Thoreau does not ask a question that is intended to engage the readers, so it is not a rhetorical question.

Based on the analysis, none of the options mentioned - metaphor, parallelism, ethos, or rhetorical question - are used in the given excerpt. Therefore, none of these rhetorical devices are clearly used by Thoreau here.

The rhetorical device that Thoreau most clearly uses in the excerpt is A. Metaphor. This is evident in the sentence "it divides the individual, separating the diabolical in him from the divine," where the action from principle is metaphorically depicted as dividing the individual into two contrasting parts.